I'm so p*ssed off right now?

If you really have your heart set on this guy, then fight fire with fire if you can. Be more flirty and charming than she is. Give her a taste of her own medicine. If he still wants to be with your friend, then you just have to chalk it up as another loss and move on. You may have to distance yourself from the friend for your own sanity. You may have to confront her and tell her how you feel. If she is a good friend, then she will hopefully choose you over some guy. After all, shouldn't friends come before boyfriends?