How do i get my gf back?

Well dude, relationships are complicated. No doubt you were and are a big jerk, but so are we all. Women are not much better, but women smell so amazing and look so awesome. So uming she and her girlfriend believe you are a jerk, you must be patient and kind. Please don't demand her affections. That will never work. I believe she would like to know how you feel, but don't tell her instead show her. Demonstrate how much she means to you. Send her some flowers, a nice card, a box of her favorite chocolates. It may take awhile, if she is really pissed. Don't let jealousy raise its ugly head. Be confident. Trust her opinions and open up to her. If she truly loved you, then she still has strong feelings for you. But if she only liked you alot, perhaps she gone. Relationships require alot of work. Time is the great healer in all things. And believe me you'll be a big jerk again someday, probably soon. My gf would tell you for sure that I've been a big jerk plenty of times. Good luck.