Best Friends or Confused Lovers?

Hi,
I'm a 16 year old male from Asia; almost 17. My social skills are pretty poor, so relationships are like witchcraft to me. Now I'm cursed.
Okay, I'll try to keep it short.
I, and She, we both got into the same school around the same time - in the 9th grade. I was new to town and she had changed school. We could relate to each other - because we were both new to the class and had faced similar problems. But we didn't grow too close. She had made many friends, while I got inside a small friend circle. I stopped attending school regularly because of my *TRIGGER* depersonalization disorder *TRIGGER END*.
Months passed. We got in touch via Facebook. I tried talking to her because I wanted to be closer. It didn't end up veing anything special - just the usual exchange between classmates. But we started to become closer after I tried to help her with some assignments almost selflessly (I failed, thanks to my overprotective parents). I'm saying 'almost' because I think I tried to help her so that we could be closer. That must be selfish.
Anyway, more time passed; some more months. We had grown closer, we would chat on Facebook, but hardly met in person. Even when we did, we would pretend we were just normal classmates - not close friends.
One night, we were chatting on Facebook. That night, she broke down (I think) and told me she was crying. I tried to comfort her the best I could. She seemed to feel better after some talking. We also realized we had many things in common, esecially having a feeling of not belonging with our respective peers and so-called friends. She proposed me friendship. We became friends. She also confessed many things about me, such as she had thought before I was a stupid poser (that's not the accurate adjective translation from our language, I'm afraid), but I was really a nice and cute guy. I replied that I was blushing (not sure if it was completely honest response, but surely I was embarrassed after hearing a complemt from a girl foe thw first time). She teased me and left goodnight messages. We met in person the next day. I was teased by her again...
After some months, we lost contact. Her Facebook account was down. It was by the end of January (it's November now). I was pretty worried about her.
Months passed. I missed her. She was the only person from school whom I missed. I don't have any strong emotional bond with any other friends.
Almost six months later (I think), we had half-yearly exams. One day, we caught ourselves as we leaving. We excitedly waved hands, but failed to get any contact information; because we didn't get a chance to exchange words.
Finally, we reconciled almost a month ago, give or take some days. We met each other in school again. After some brief and awkward conversation, I realized she has a Facebook account. I'm not good at talking in person, so we didn't speak much then.
That evening, I found her on Facebook. After many excited messages, awkward moments and very subtle flirting, we were united again. I was really, really happy and excited. We had exams going on in school, so we were more or less bound to see each other. Those days passed pretty much magically for me.
Almost a week later, on that fateful night, she asked me if I like someone (romantically, surely she meant) and her fingers are still crossed. I was hesitant to admit, but realizing she said 'her fingers are still crossed', I admitted to her that I like her a lot. What followed was a series of emos and OMG stickers. She said she couldn't believe it (with excitement, if I picked up correctly from those Facebook messages). She lamented that she was not good enough to be liked by me, so I must be joking. I kept explaining to her that I was not, but then she cut off. I feared that I might have offended her, so I left apologies for her. Then also, she seemed to really like me, so maybe she was taking time to think or maybe writing a love letter; I hoped.
The next day, we met in school again, exchanging brief smiles as usual.
After getting home, I tried to contact her again. After she was online, she told me she had problems with her phone last night and called me silly for thinking she would be offended. After some usual exchanges, we admitted we had thought about each other a lot after that conversation. While neither of us said "Let us be lovers now!", it was heavily implied already. So, after some silly conversation, she said it would be better if we finished our studies first. We settled for that. Then we talked like nothing special happened.
The days that followed were more exciting. She flirted with me less subtly, I played along.
I learned more things about her; her dark secrets.
As the days progressed, she was becoming depressed - her messages implied. I learned of her conflicts with her (single) mother. She has toldme before her mother worries about her, but now I also learned that they have regular conflicts about her academic performance. She also told me how her life has gone downhill. She has to pretend that everything's fine, while she is broken inside.
Here comes my life story. My parents are emotionally abusive. I still live with them. I was also a self-harmer, but had been forced to stop because of some utterly ridiculous reasons. That's all you need to know for now, I think.
So, I tried to comfort her by telling her how I live a life like her, pretending everything is fine while nothing is not. She had told me long ago (before we lost contact) that she cuts herself, but I decided back then to not dig into the subject, fearing that I would hurt her, instead merely acknowledged that I do that too. Now, I thought I might make her feel less alone by telling her about my 'blade scars'. Bad idea.
Her self-harming is pretty serious, so a separate thread would be more appropriate. I'm not going tk elaborate about it much here, but I learned that she hates herself because she can't meet her mother's expectations. I felt so bad for her. I wished I could pull her into a tight hug and tell her verything is going to be alright; none of this was her fault. The hugging wasn't possible, but I have told her I'm with her and none of this was her fault. She shouldn't hate herself. But she cointinued to feel depressed and upset with herself. I felt like she needed to know that she is loved by me and I love her for what she is and what she will be in the future. So I told her. She later told me she was fine, but it didn't feel so to me. The following days were as grim. She had cut herself again and told me about it. She would sometimes send pictures of her wounds.
(I can't be sure of the exact order of those events.)
Our results day were approaching. Naturally, she was becoming very upset and stressed, if I had felt correctly.
The evening before the result day, I found out the series of messages that would lead to the heartbreak.
She has said in those messages that she had to tell me something. She can't love me, because she already has a lover, whom she has broken up with after 2 years of relationship. She still loves him a lot. She likes me as a good friend, nothing else. She always respects my feelings.
I had been sleeping prior to reading those messages, so with a sleepy brain, I didn't feel any strong emotions, but told her instead that I was fine with that and I love her as a good friend.
That wasn't an honest response, but I respect her feelings, and I didn't want to lose her. I also told her we should talk about it (later). She agreed.
Later that night (very early morning), she wanted to hear what I wanted to say. I was hesitant, but started with saying that I respect her feelings for him and for me. I just wanted to know about her flirting. Had she been serious or was it just fun? She denied any flirting, even seemed somewhat confused and angry. She told me that she has never even thought anything like that about me and had always seen me as a friend and such. She also said she doesn't know what have I thought of her. I responded I see her as friend too and we are still friends. She asked me if I was okay and I responded that I was fine. We wished each other goodnight.
After that talk, we were still friends. We talk regularly, like good friends. She still flirts with me if she is in a really good mood. Maybe she doesn't realize she's flirting.
Her relationship with her lover seems to be inconsistent. Though she said that they have broken up, they seems to be in touch. From what I have learned from talking with her is that she loves him more than her life (sounds too dramatic), but he doesn't want to be together. When asked about his personality, she has told me he was careless about himself. He smokes, he was a bad guy and such; but she still loves him a lot.
Just a couple of days ago, she had become very upset again, seemingly depressed. The next day, she told me her lover doesn't deserve her. I told her that I know he doesn't deserve her, she is a good girl and she deserves someone better. I tried to not sound selfish, not sure if I succeeded.
She tells me many things; she says sge doesn't share those things with anyone else. I try my best to be there for her, though not physically.
While she seems emotionally manipulative, I'm not blaming her. She has been emotionally abused by her mother, I believe; like me.
I respect her feelings. If she thinks it would be better for us to be friends than anything more, I would play along. What saddens me is that she made the first advance and then stepped back. I don't think I would have ever told her how I feel had she not made the first advance.
Could it be her guilt affecting her?
At this point, I don't care much about whether we are friends or lovers. I just want her to be happy.
Please help us.
There are many details that I left out, so please ask me if you need to know something.