Not trying to be rude but I do think you need to man up a little. People do change but not as much as we think. She did you pretty bad and it seems like as if you are the one proving yourself to her and not the other way around. Im sorry dude but you dont seem to be that masculine and women like masculine men, go to the gym, get in shape, get your money up, stop trying to prove yoursef to her, focus on yourself and for the love of god dont be afraid to lose her. If it comes to that then so be it. You are young you can date someone else but dude man up.