I am so confused !

So my boyfriend and I have been dating for almost A year and a half. I've never been the one to ignitiate to sex. & most of the time we have had sex he is the one controlling and doing most of the work. One day he told me he wanted me to go on top & take control, which I haven't had a problem with in my previous relationship. Except when I did... I was super uncomfortable, I felt as if I wasn't good enough, I didn't feel attractive, I wasn't going at his speed. (I couldn't go at his speed!) I was useless, I didn't want to do anything, and I didn't want to disappoint him but he noticed my facial expression& asked what's wrong..... But ididnt know what. it made me so angry, I started to cry &a more tears came because I was mad at the fact that I was crying!☹. He asked if he did anything wrong, but I said no. He told me to go at my pace& do whatever I want, but I couldn't. And idk what to do, is it me ? Him? Us? I've never had this problem before.