hi i am new to this sight and just wanted to say that i have depression and problems with people and talking i am a cutter and very suicidal. so i kinda need some help and ideas on anything that could help me. i am only 18 and im a very shy girl

I just don't understand my "family". I leave my purse and wallet out on the table and they come and go through it. They just pick my wallet up and flip through my check book. And when I said something my grandmother got mad. She just got mad and smarted me off, then walked away. It's like this all the time, it's like I'm supposed to let them run over me and do or say whatever they want about me or my stuff, and if I say anything I'm a bitch or I don't know what I'm talking about. Honestly it makes me sick just to be here. Sometimes I just feel like I can't take it anymore, like my time is over and I should just commit suicide.

So i've never written a post ever on any forum, ever, and since things have changed for me recently, i'd decide to give this a go. Might not come back to this but i want to get whats in my head out there and see if anyone has anything to say about me and my problems.
My problems: I care about my family too much. I'm almost certain that I have depression, mild anxiety and a myriad of other mental health problems but I've never been properly diagnosed because I care about my family too much to have them worry about me at all. I also come from a culture where mental health is not a 'real' problem, but rather a thing for the weak or the bored.
I think about death a lot BUT i'm not suicidal. I'm fine with death and i'm not scared of it but I would never be able to go through with it as long as my parents are alive because I can't put them through all that pain. If they died though, I would have not much of a reason to keep going, but that is not the point of this post.
I've always been very aware of my issues and i've always been able to talk myself down in my head like there was a third person that tells the two conflicting voices in my head what to do. This third voice sounds like a trusty friend, insightful parent, or even a advising counsellor, when i think about it. This voice knows what people views as normal and suppresses my arguing voices to make me seem 'normal'. It usually takes effort but I know it works because everyone thinks I'm still this smiley, happy girl, which really hasn't been the case since about 7 years ago (when my first encounter of death in the family happened)
My dog (who's been with me for almost 15 years) died yesterday and I was sad but it wasn't a fearful, regretful sadness. It was more of a "i'll miss you" and "we've spent good time together" happy sadness, though it was really sudden and shocking. I still miss him but I don't think I'm doing too bad. My parents on the other hand haven't been able to sleep, eat, not spontaneously cry, and not talk about morbidity every couple of hours. They also hug me a lot because they think its comforting for me, and probably themselves too.
I guess what I'm saying is that is it weird that I'm so aware of what I'm almost sure I have? Does this mean I don't have these mental health issues because it doesn't really affect my daily life and I know what triggers it, how to control it, and what works/doesn't work? Do other people with mental health issues experience this too?
An analogy (if you're still reading): I deal with my problems like dealing with my period. When it starts, I know what I can do to not let it leak out for the world to see. I know what the best way to deal with the dirty pad/tampon is, to chuck it out (feeling all my feelings/non-feelings but in a physical location where no one will see me then throw them out or at least leave them where they can't be seen). I clean up after myself and flush the bloody mess away (make sure no one can physically see or pick out that I have problems at any point of any time)
What do you think?

I've been looking everywhere online for advice, and everyone I talk to says I should go to some sort of psychotherapy. I don't know about it, though.. I finally had the courage to tell my sister what's been going on - I've been hallucinating, I can't sleep too well (3 hours a night is my current average), I get very nauseated whenever I eat so I've lost a significant amount of weight. There's headaches, dizziness, fear (of nothing, really), anxiety, trembling, it's hard to breathe sometimes, too. I had a panic attack about two weeks ago, it lasted for maybe fifteen minutes. My dad says he used to have panic attacks, and I read somewhere that it's more likely for me if it runs in the family. I can't stand being alone because these hallucinations get worse when I am. I'm also being cold(-hearted) lately towards my mom and sister. I feel very anxious -at night especially- and self harm calms me down. I started scratching my wrists and digging my nails into them. I don't want to do this, but it's become very addicting and even soothing. My sister wants me to see a psychiatrist, and put me on anti- depressants. What should I do about this? Please help.

Okay, I've been searching for help. I have a problem. Let me start from the beginning.
My eldest brother suffers from cerebral palsy, and my entire childhood- my mom did not stay with me (parents are not separated) and my dad isn't exactly the loving type.
I have been a liar (without meaning to) from my childhood, and I have been sexually abused when I was a child (it didn't feel like an abuse, though)
Growing up, my elder brother (another one) kept dominating me or comparing me with my cousin brother who stayed with us. My brother would even force me to do things I didn't want to. He literally used to twist my arms.
Slowly, I feigned love for him. It happened on it's own. I actually believed myself. I knew I found him irritating and unwanted but still I respected him.
The somewhere around highschool, I got into a relationship and got cheated on. Yes, it was my first love.
It hurt. I was in a boarding school, I felt alone but never cried. I tried to take my life for reasons I can't remember. That phase of my life is a blur.
I thought everything would be okay.
It didn't.
My dad took me to a therapist, but my mom felt I was possessed by a spirit.
I'm 16 now, but I still haven't rebelled or gone against my parents.
Anyway, I never met the therapist again but I had to take part in rituals and what not.
Back to my brother, he manipulated me and made me look bad in front of my parents.
Being the weak, submissive sister I was, my parents never thought it was my fault.
Moving forward, he even made me lift up my shirt because he wanted to see my body type. I was obsessed with losing weight, I was dumb, I did it.
Now he would hug me weirdly and said I never hugged him properly. It sounds funny but he said my butt was too outwards, it should be inwards towards the person I was hugging.
Now, back to my elder brother, I know that he is suffering. But he does so many things to get attention. Shouts, screams, cries all day long. I'm suspecting that he even feigns illness. It isn't that we don't love him, we do. We do everything he asks, but still...
My father has never been affectionate. But he has always been there for me. We're good friends.
My mom, I don't know. She always makes me feel that marrying dad was a mistake. We're good friends, but... I feel trapped. Everything I do has to be under her.
I can't do anything on my own.
I feel suffocated.
So, around five months ago, my elder brother died. He was an alcoholic. He hit me, we fought. I never spoke to him again. I guess, I never will. I hadn't seen his face for a week or so, and when I did... I knew it was lifeless but it didn't look that way. I can't accept what happened. I'm angry that I couldn't be angry at him anymore. I don't know.
Now, I'm rude to people. My teachers say that I have lost that shine. My writing suddenly improved. I can laugh but still I feel different. None of my friends talk to me. I only have online friends.
I feel so alone.
Sadly, I think I like it that way.