My boyfriend and I just broke up.. thought id be with him forever... what do I do to get over him?

Start by reading the stickies at the top of this forum. A little more detail into your story would be nice as well. Why did you break up? How long did you guys date? Etc...

Takes time to get over someone. It all depends on how much time and emotion was devoted to the relationship.

Get involved with a life of your own.
The more you get out and enjoy the less time you have sitting around dwelling on how much you miss him.
Go out with friends, find hobbies, find things that interest you and do them.

Kctiger and nohelp4u said it. Read the stickies, a lot of good information on them, including "No Contact." That's a big one. Think of anything you wanted to do while the two of you were together, but you didn't have time or couldn't for whatever reason and go out and do those things. Hang out with your friends, take up a new hobby, join a gym, sign up for some classes. There are all sorts of things you can do to take your mind off things.