Relationships go through rough time, the only way to know for sure that you want to be together, sometimes is to get some time apart. Sometimes that makes a relationship stronger...
You don't say how old you are, but it sounds as if you are both young (is that right?). Relationships, when we are young, aren't always meant to last. Sometimes it's best to date a lot of different people -- it really does help us to find out who we're compatible with. And sometimes, even when we really, really love people, it jsut doesn't work out.
In uncertain times in a relationship -- the best thing you can do is just give it time. Don't push it. If the situationw ere turned around, and you were the one who was uncertain -- would you want someone hounding you? No -- so give him some space to figure it out. It's really, really hard to do -- but hard is not impossible, right?
Occupy your time -- reconnect with friends and family, read books, watch TV and only allow yourself to think about him for specific times during the day. DON'T let yourself just thing about this endlessly.
Let me know how it goes...
Give it a minimum of one week and then reevaluate where things are. Then give it another week to see how YOU feel. This is a traumatic time for you right now... and it makes it worse that you have to see him all the time.
Is there anyway you can work without seeing him?
In two weeks, you'll feel a little differently -- you won't feel so desperate; you'll feel more clear headed as to what you want.
Sometimes when a relationship ends -- even if it was a bad relationship -- we freak out and want just to be back with that person, then given a little bit of time and meeting other people, we realize that we can do better.
This may not be your case-- but still, give it two weeks to see how you feel. He's not going anywhere... he'll still be there....