Lost the love of my life? :\

I recently came to terms with my sexuality and last month I finally looked in the mirror and was able to admit to myself that I was gay. Two years ago I fell in love with one of my close friends and he fell in love with me too, but I wasn't ready and I was terrified of him and myself so I rejected him. I broke his heart and he moved on from me. Now he's found someone who makes him really happy, but I feel like I made the biggest mistake of my life and I regret pushing him away. I guess I'm just feeling really depressed that I gave up someone who I think could have been "the one". What do I do to get over this? I can't stop thinking about him and I've started cutting myself to cope with the emotional pain... :\