Why does he keep going MIA on me ?

I been knowing this guy for 6 months now the first time after sleeping with him, He all a sudden went MIA. A month went by and he contacted me, we talk and he said my attitude was bad that's what made him stop talking to me.. Now this month we started back talking and I spent the whole weekend with him at his place, now he's doing the same thing again. I don't think I had an attitude over the weekend or did anything wrong but I been texting him for days now, no reply. I even called and it sounded like he didn't wanna talk and hung up the phone. I really don't understand what could be the reason & it's not like I can ask him because he's not replying. I really caught feelings for his guy and he's blowing me off :(  I'm thinking he chill with me and realized he didn't like me but even after I left we was texting. & yes we had sex both incidents