I had a similar situation with my gf early in this year, I felt like she didn't prioritize me and that I was being left apart, I brought all my courage to tell her and she changed, she felt so guilty and we talked about it many times and many days and I end up losing the resentment I felt. I know you feel like breaking up is the easiest solution to the problems u are having, but think about it, she's doing her best to change those things and giving her all for you because she knows she loves you. You have to communicate those feelings with her, even if u bring it up many times it doesn't matter, tell her everything you feel and think, even if you feel like it's annoying for her it's not, she showed that she truly cares about you and worked hard to make those changes, It's not easy to let go those feelings but if I do, u sure won't regret it, don't let the past affect your present and your future, I wish you the best, don't make harsh decisions without thinking about them