How to get over a breakup.

My boyfriend of three years broke up with me yesterday citing his unhappiness. He didn't have any particular reasons for it, just said he had been unhappy for some time and wanted to end things. I don't understand where this came from and none of it makes sense to me so I'm trying to cope and move forward, but I'm really not sure how. Any advice on how to get him out of my mind would be greatly appreciated. 
His follow-up was that he wasn't happy with himself, which was causing him to be unhappy with our relationship. And he isn't saying he wants to split forever, he just needs some time. To me that means he's trying to let me down easy and giving me false hope that something else may happen.