Can relationships be harder for persons with OCDs?

Hello. I have OCD, and I noticed that having relationships is really hard for me. In most of the cases, I tend to give in and expect too much, and I keep thinking of the beloved one day and night, suffering incredible pain, to the point of crying, even when it is just a crush and nothing has really hapenned. I think this is not just another of those relationship problems every person have. I think I suffer way too much.
I aways thought that I was overly sensitive and that I was the only person this way, and that I was not normal. I notice that most of my male friends only talk about sex and soccer, and I just can't see women as a toy like they do. That is why i thought, for many years, that I was not normal, until my doctor told me that it is completely normal to be this way. But I still think that I suffer way too much! Most of the time I suffer from things that have not even happenned! They are just inside of my head, I keep daydreamming and the strong feelings come rushing into me. Maybe this has something to do with my Anxiety disorder?
And it has been a colossal pain in every relationship I have been, aways wondering if the girl really loved me, how much she loved me, what would happen in this or that situation and so on. They seem like obsessive thoughts, but slightly different from the normal OCD thoughts I have.
I can't think of a normal and happy relationship as I see with those around me, with both people being happy, laughing and getting along when they can, without stress or paranoid need for love. I don't even know how I could deal with break up cases I have seen, where couples married for over 20 years divorce, finding out about cheating.
I can't even work, study, play guitar, draw, write or do anything else because of the intense feelings inside of me. I am never in the mood.
This is the situation I am in right now. I had a girl bestfriend in college, but she gave up the classes 4 months ago. I loved her as more than a friend, and after she began taking breaks from the class, I felt incredibly scared and alone in the classroom even with more than 20 people around me, all of them really close friends. I felt helpless, lonelly, insecure to the point of crying at home, and the feeling lasted for a week. Then I called her asking if she wasnt comming anymore, and she did return to the classes. A few months ago she definitelly left, and I can't stop thinking about her, day and night, and I even dream with her.
The pain is excrutiating and colossal, something that makes me really depressed with a heavy weight on my chest, and I even question suicide. I just want to see her again, and talk to her.
I don't have any sexual desires with her, and found out that I can't touch myself thinking of her. I just lose all my libido.
She has a boyfriend, and I felt extremelly guilty for liking her, and even for talking to her and saying that I liked her. She accepted it and was really kind, saying she only saw me as a friend and couldn't do anything since she was in a serious relationship, but I still feel really guilty for that. It is almost like a despair.
Maybe the feelings are intensified on people with OCD, or with Anxiety Disorder? I don't know. This is all new to me since i just started researching about OCD a few months ago.
During my last relationships, I had the need to stay in contact all the time, be it on the phone, internet or personally.
And everytime i thought on the woman I love, I feel sad and pain, instead of feeling happy and pleasure. I aways wonder if they will cheat me, betray me or hurt, instead of just enjoying that I am in a relationship.
It seems like the Spikes I have with the obsessions, but as I mentioned, subtly different. It comes like a juggernault and destroys me, leaving me in pieces about something that didn't even happen, in the case of crushes for example!
I don't want to keep suffering like this in future relationships. Any advice is welcome.
Thanks in advance.