Was I Bad At Sex ?

I met this guy we had been talking for 5 months , I felt comfortable with him to have sex with him , he took me on dates , bought me gifts , but after we had sex he stopped talking to me. It was so weird , I don't want to chase him and try to make him talk to me. I guess our sex wasn't good , I asked him what did I do wrong and he said "nothing" I tried to start a regular conversation with him, he never responds , I feel so stupid . I guess I'll just move on and use this as a learning experience . Has this ever happened to anyone ? Should I keep trying with him or just delete him from my life . ( I havnt texted or called him in 2 weeks since we had sex )