You haven't told us much so we can't assess your situation. You say you're 'mad at yourself' but you don't explain why. My guess is that the girl you're talking about rejected you after you came on to her or something, but I could be wrong.
well you didnt say to much about it. So I would say yea normally when you like someone you want them to be happy with you not someone else. But i dont really know what you are trying to say why would you be mad at yourself?