I always used to get obsessed over girls like this guy, and it's f***ing hard to get over it. And u gotta be careful it doesn't turn into depression when they dump u, cuz they almost always do in that case. There's an article here about the link between depression and breakups:
http://www.medicinenet.com/script/main/art.asp?articlekey=36188
Anyways, what I found works best is if u just get out there, and find urself a gf that u might not like as much as her, but who u can respect, then stay with her for a while. Don't set ur standards too high, ur goal isn't becoming a dj overnight its just recovering ur self esteem. Then, when she gets obsessed over u the way u got obsessed over the last girl, maybe you'll start to feel like your life isn't so bad.
You might not have the same experience as me, but the idea is to just drill it into your brain that people like you.
Also, as for what your feeling about her you might feel better if I pick that apart for you. Basically, humans are animals, just like any other, except that we've evolved a bigger brain. The number one goal of any animal is to pass on its genes.
This means that there are three things that are important to you:
1) Not dying
2) Passing on your genes ie getting laid or having the potential to do so
3) Helping your family with 1) Not dying
If your brain, which is an important part of this survival machine that is you, detects that you aren't fulfilling these goals, it gets unhappy. Really fu**ing unhappy.
Evolutionary psychology predicts that after a while, not being able to get a date should be about as stressful as getting daily death threats, or living in a war zone, or losing a parent or sibling.
Keeping this in mind your first step should be to try and keep your current girl, but if u can do that find another one fast. Any one will do, don't be picky.
As you pick up the pieces you'll start realising what a ****ty part of your life this one has been, and how much better your life can get. Hell, you'll eventually be a DJ and be mackin all the girls, but one thing at a time.
Good luck