Can't get over an ex girlfriend and I'm tired of it.

Hello everyone. For starters, I'm a 21 year old dude and Im currently at a university doing a degree on classical guitar. My life is alright all around, although I do have a tendency to overthink a lot and make up excuses to avoid my problems.

So, to the point I suppose. I had a girlfriend for 6 years (we started out pretty young, yes), and we broke up 2 years ago. It was peaceful. I was starting to get pretty depressed, couldn't get into college, barely had any friends, and I just hid away in my computer games all day mostly. We broke up because it was starting to affect her too, and I agreed it was for the best.

However,, 2 years later, I'm finally getting better. I'm in university already, I've got things kind-of figured out. I'm definitely not the same depressed dude. I'm currently seeing a girl, nothing serious, and I've had a short-term girlfriend last year (went for bout 3 months, then I broke up because she was an overjealous person). I have some friends (althoough I don't really get invited to anything by anyone during summer vacation so I just had to learn to enjoy my own company), but there's always the same questions in my mind.

Does she think about me? Does she miss me? Were we 'soulmates' and my stupid depression ruined everything? Will I ever find anyone like that again? Will I ever get past this whole thing?

I think about her almost every day, I dream about her most of the time, everytime I do something I'm proud of I think to myself "Damn I wish I could show this to her." We haven't talked since the break up much; Mostly just wishing eachother happy birthdays and merry christmas. Recently I messaged her because of her sister, since her sister was going to do exams to my university, and I offered to show her around and be her "guide" (she would be completely new there and didn't know anyone, and that can be overwhelming). She said thanks but that she wasn't applying for that university after all, but that she was really happy that I offered that.

All in all, I really don't know what I should do. At this point I really just want to end this whole ordeal since I neither have her nor I can forget about her, and I haven't felt the same with anyone else. What should I do?