So worried...how should I go about this?

We had an annual celebration night for my karate club last night, and it was at a club and everyone was really drunk by the end of it... there's this guy who i don't know well but i see at training all the time and i usually just say hi to .. i ended up going back to his place and having se.x with him afterwards. it was really good, but stupid none the less. How could i avoid the awkwardness when i go back to training tomorrow.. i think others have already found out that we did it... :/