I had drunken sex with my best guy friend???!?

Last weekend I had drunken sex with my best guy friend we have been friends for 7 years nothing more than friends. I don't want to be in a romantic relationship with him. I feel so bad I got that drunk I seriously blacked out I don't even remember it! I feel ashamed I ruined our friendship he's been texting me that he wanted to be more then friends for years and he so happy we are now. I don't know how to tell him it was a drunken thing and I don't want him as a boyfriend. He sent me flowers and candy 2 days later. It's really weird how of I get myself out of this???