How is this girl affecting your life soo much?
More importantly why have you let her affect you even at all?
I think you feel that she was using you, in order to gain advantages over your artistic/poetic friend. Do not let her methods of sabotage be psychologically detrimental. Which relays back to my original prognosis that you may possibly be 'over-protecting' your friends.
Instead of waking up to the fact that she is nothing in your life, you are still adding details to the design of your perfect subconscious monster.