Now is the perfect time to find new people to hang out with. I know you don't feel like it - you probably want to climb into bed and stay there for the next six months (BTDT). BUT, if there's any way you can force yourself out of the house, I strongly suggest you do so. Make a promise to yourself to speak to one new person a day, even if it's only "good morning". Do one new activity per week, even if it's only walking through a park you've never visited. If he hears through the grapevine that you're happy and having fun, it's going to be a lot better for both of you than if you're crying over him, believe me!
I hate to be cynical, but one thing I've seen over and over again in my lfe is that if he knows you're still pining over him, he'll come crawling back when it doesn't work out with the new girl. Everything's fine for a few months and then it happens again, but this time you feel doubly foolish for taking him back (again, BTDT). Not all guys are like that, but a lot are. I would hate for you to go through that if you don't have to.