<human>: Can you provide a brief overview of the text?

My boyfriend and I have been dating for 4 months. For the past week he has been indifferent and whenever I try to insinuate anything sexual or try to be more intimate, he brushes it off. 

Around a week ago, we had sex for our first time and he threw out his back trying to lift me. (No, I am not fat. No, he is not weak. I think it was just the weird position- I was lying on his bed with my legs wrapped around his waist. He was on his knees and bent over me) The entire situation was just bizarre and a little ridiculous. I apologized to him afterwards since I feel like it was my fault and he apologized too. We haven't mentioned this situation since that brief moment. Yet, I have a gut feeling that this may be the issue.

I'm quite frustrated because I feel like he doesn't want me anymore and that our relationship is slowing to an awkward halt. He isn't as sweet and clingy (for lack of better terms) as before. I really don't understand why he is acting like he is and don't know what he's thinking or feeling. What should I do? Break up with him?
<bot>: Boyfriend has not wanted to have sex again after our first try and has been distant. Why is he like that? What should I do?