Um what do I do when Ive totally messed everything up with a girl that I cant get out of my heart?

K so about a year ago I met a girl. we will call her red. Now I met red in a photography class. It was the only class we had together. She was a dating a guy and I was dating a girl. so photography became a place where we would hang and talk. We would lay in the dark room and talk about everything. shortly after meeting her. My girlfriend and I broke up. I was heart broken and still wanted her. but whenever I came to this class I seemed to forget all of it. Red just made me happy. I didnt really have any feelings for her. I just remember being friends. One day out of no after wrestling I really wanted to kiss her. and thats where it all starts. Afterwards, each day we hung I had to keep telling myself were just friends. I would skip days so I would lose that feeling for a bit in hope that it was just a passing thing. It wasnt. Everyday it would get stronger and harder to resist my feelings for this girl. Summer came and we parted. I figured it was the end of our friendship. I was sad, but I let it happen. After summer on my bday in sept.3 I invited her to my bday, Red and her boyfriend showed up and I Liked the guy a lot he was really cool. But I couldnt help but be attracted to her.I then decided I couldnt be with out her though. AT least not in my life. So Instead of heading to UBC I stayed home. I wanted to be near her. afterwards she called me up and we started hanging. and everytime it would progress. I eventually told her that I loved her. Even though she has a boyfriend. That was a mistake. I thought she was in a stable state with her BF. SO ifigured no harm no foul. It was harm. There was foul. I became a danger. she started to "fall for me". I got scared and pushed her away. BADLY. Seriously badly. Like Ive done everything. Cut her off from texting me. B;locking her on MSN FACebook. I went all out. Because I was afraid of hurting her. and I guess I ended up hurting her. I didnt mean too. I love her. very deeply. I often dream about her without any intention. It just happens. I fall asleep and shes there and we talk or hold hands or even kiss. I miss her so much. I dont know what to do. I think shes done with me. which is good because I cant cause her anymore harm. Im trying to move on so badly. But Its just not working.. Everyday I wish that hadnt done what I did. BUt I was just causing her pain. I was to much trouble for her to handle. I have OCD and it causes me to overthink and overanylize. to the point where I do rasch things without thinking. I dont know. I just want someone elses opinion. PLz help