Im very heartbroken right now what do i do about it?

well me and my girlfriend cynthia we are young i love her so much im gonna be fifteen she is fourteen and me and her have been together for 8 months i would do anything for her and she doesn't want me anymore so i guess she is actually my ex girlfriend now and she is all i have been able to think about for the past week and all my thoughts just keep growing and growing and my heartache wont go away somebody please help me im desperate i have never known pain like this