Me and this one girl had a thing for a year, and neither of us made the move and it ended up with her blocking me, but eventually we started talking again and we attempt to see how it would work out. In the end it didn't, but we stayed as friends.
Spending a year in this "friend-zone" and then getting burned, I learned a lot of things about relationships with people.
You may not believe it, but I know exactly what things you're feeling right now. The problem here is that the wounds are still new, so they will absolutely hurt.
All I can say is this. If you really value that relationship with her, you need to make sure to give her some appropriate distance. It may sound like a very jerk-ish thing I'm saying to you, but this advice is probably going to save you from the world of pain I got put in for not following it. I don't mean completely stop talking to her, or stand a couple meters away from her on the street. Instead, you gotta make sure you're not obsessing over her, that you treat her like a friend and that you prevent yourself from giving into your emotions.
Maybe, if you're really lucky, she might one day come back to you, and everything can be perfect again. But as it stands, you don't want to be that guy who won't let it go and comes off as a creepy bastard. You're better than that, and you know you can treat her better than most people would.
As for the pain you're in right now; best thing is to try to distract yourself until you can have a moment of clarity and calmly release those feelings. Meditation, musical instruments, video games etc are all great distractions. The aim isn't to forget, but give yourself some space and time so that you can eventually come back with a clear(er) head, rationally think about the problem and then try to expel it and move on.
