I can't get her out of my dreams?

Let me clarify how horrible this person is before I finish this. She doesn't want anything to do with me after four months of being together, talking every day on the phone if we couldn't see each other. We lost our virginity to each other. But throughout the relationship she wouldn't fight when we had a couple fight. I felt like i was fighting for our relationship and she didn't want to try. I made all the effort and she would act sad all the time. She said to me in a text that i had to literally pry out of her that she wasn't happy when we broke up and that she was having more fun with her friends than with me. Everything was going smooth until I couldn't handle how much of a B^tch she was being. After we broke up it really showed. She wore a bar� through the hall ways of our school with all of her friends around her like some type of prep godess that's how dumb she is(after we broke up). She lashed out. She flirted with guys in front of me, told her friends in front of me that she had a date, went to the prom with my best friend, ignored me like i wasn't even in the room. A little side note by the way, how can you do that to your best friend that you've known for two years before that and all of a sudden act that way? She pretty much turned into a completely different person and I was so mad all i could do was yell at her from that point on. I couldn't stand the sight of her and sooner or later i didn't look at her, and i didn't talk to her. Every couple of weeks after i would text her to try to find out the reason about Why this all happened. She would act like i was being unreasonalbe, and like a jerk so she wouldn't text me after i asked a question. So i don't know how long it's been since i've talked to her, but last time i did she told me not to text her again which i took to heart because it's not worth bringing up bad memories and heartache. But all of a sudden i keep dreaming about her. I had a dream last night, we were laying on a bed, in a rare occasion i was looking through my eyes in my dream. We were still broke up but she was acting nice, like her old playful self. I took and sat her up on her knees and moved her so she was positioned outside of my legs (we were fully clothed so don't get any ideas) and than we started to make out. She asked me what i was doing before i did it and it seemed so real, i didn't want it to end. When we stopped kissing she got off of me in disbeleif of what just happened, but not in a good way. And than the dream ended. I keep having dreams not quite like this, but dreams with her in it. What do they mean? If i don't feel love for her and only hate for the things she did to me than why did i have this dream?