How do I move on?

I lost my best friend because I did a stupid thing and fell in love with him. I made a huge mistake by ending our friendship because the pain of loving him while he didn't feel the same way back was eating away at me while my depression was too. I realized what I did was selfish and that our friendship meant more to me than my feelings, but by that time it was too late. He won't forgive me for hurting him because I left...

He was the only person I could tell anything and everything too. He made me happy, he had been my escape from depression for years, and now... he's gone. I begged and pleaded for his forgiveness, but what I did just hurt him too much. He thinks I never cared about our friendship since I ended it out of the blue... I don't know how to move on from him though... I miss him. I miss him.