I know this is long outdated, but on the topic at hand; I went through this recently myself (barely 6 months ago) and it was one of the hardest times of my life, where I would've given anything to reverse time and undo it.
But in hindsight; it was an important step in development for me. What I gained from it in the long run was invaluable; the same as every other misstep in my life.
I was crying so often, I was borderline dehydrating, yet I pushed forward and kept doing my own things and things eventually got better. New places, new friends, and I began to find girls who I thought were even better matches.
I accept now that me and her didn't work romantically, but I think what hurts the most for me wasn't the romantic breakup; it was more that we were so emotionally close and truly friends, that she wanted me out of her life entirely.
Simply because I'm so intense and she feared I would try to rekindle it; which, at the time.... yeah, she was probably right in that concern.
So it's not like she even hates me, but I doubt we'll ever be able to talk again, even just as friends, and if anything hurts most; it's that.
My point being, to anyone else who sees this topic with similar issues; just keep going like you always have. Things get better and you never know when someone new might show up again. And you probably never would've met them at all if you hadn't experienced this setback.
Some things we consider 'bad' might actually be blessings in disguise. You just never know.
You're allowed to feel sad, cry, and get it out; but you can't just become stagnant because of it. Then those feelings will consume you and you really will be lost.
That's all I have to say on the matter.