Hey,
That's really sad.
But I've seen this happen to so many people in my lifetime, and if you want the best advice I think I can give (in general), it is this:
Please don't sit around and think too much of the break-up. Instead what helps, is to get out there or to find every dating and contact site on the Internet and start to talk to other girls. It doesn't mean that you should complain to them about what happened, it is just to view your options. Get talking to a few that you think you would like, and take it from there and see what it leads too. Just don't get into a relationship straight away, and don't come off as someone who is just on the rebound, but rather as the person you are, and hopefully you can meet someone new.
I know it's tough. Trust me.
But it's better to get cracking on your options than to despair. :smile:
Hopefully you can find your own ways.
Take care in the meantime.