I know what that feels like. Call me slow, but up to now I didn't know that it was part of my condition. I remember this happening so many times in my life. I am not a teenager anymore but my exceptional memory won't let me forget. I used to feel so obsessed I would be a walking dud and only respond to anything if that person was in te room. Even now in my twenties it happened to me. I thought I could handle it cause I have more brains but no, it makes no difference. Weekends were sheer agony! The only thing that helped me was removing myself completely from the place where I could see him. It takes me about two weeks to forget those feelings whenever I see him again. I also feel that there is this connection that is surreal but for me its too late as we are both married and I am happy with what I have but there's this pull towards him that's hard to ignore. All I can say is, don't see her anymore! Change schools if you have to. I am just scared it will happen again with someone else. I have become sort of a recluse to try and avoid it and I have become more spiritual since. But its still not possible for everyone with that problem.