I got screwed over what should i do?

Don't go after her. It sounds like she can't make up her mind about who she wants to be with and it's really selfish and mean of her to lead you on like that when she has a boyfriend. Don't think that it's because of something you said a long time ago, your feelings are still the same. It seems like she knows that you like her. I think she just treats you like a guy friend to go to/fall back on. Just realize that, unless she has said, "i like you and I want to be with you" (not knowing more about her or your situation that's all I can say), it doesn't seem like she likes you in the same way/the same degree that you really like her, and you really like her. It's not your fault that you like her, but it sounds like she's playing your feelings.