I agree with curley above. She is a game player, and this is not the sort of thing that you build friendship on. Whether or not she is bipolar is really her business. That's sort of beside the point as to her being inappropriate with you. It's best that you just let this thing go and move on. I'm sorry you got hurt. Getting back involved with her would just be asking for more hurt. It would not be good for either her or you.