What to do

Hey Wassupp y'all can just call me C,

I have a girlfriend and we have been dating for like 9 months. And it's been great, but recently I have just been realizing a lot of things that I just can't stand. It's like our wavelengths became our of sync. She's really sweet, but if I break up with her I feel she will hate me....

that's one problem in my life. Another is that I have this thing with masturbation, every time I do it I feel empty, lonely, sad. My mood changes and everything. Idk what to do. Any thoughts?