If you really want to get your girl back, as in the previous posts, you need to talk to her even if she won't listen. Even better, do it while she's in front of her friends. It's probably going to take a lot of courage, but if you do it, she'll probably understand you and then all of her friends will see that you actually care about her. Even if she doesn't want to make up with you, wait a few days/weeks for her to cool offf, and then do something really nice for her (i.e. flowers, poem, etc.) If you show an act of kindness, it means you really care about someone. Other than that, you're on your own! =P Good luck!
Forget about it and get on with your life. You can tell the truth to people but that doesn't guarantee that they will believe it. Their loss. Plus when you are older you probably won't even remember or think about it because it isn't going to effect the rest of your life.
