Anxiety attacks during sex.

I’m 16 and have been dating my boyfriend for nearly a year now yet I still get anxiety attacks sometimes during sexual stuff. The first time this happened, was when we made out for the first time and in the middle of it I couldn’t breathe and was on the verge of tears. Then, a few weeks ago we had sex for the first time and I had an anxiety attack afterward. So my immediate thought was that it was probably just the first time we do something new I get freaked out and have anxiety. However, just the other day he was fingering me (tmi whoops) and I had a major anxiety attack where I was sobbing and unable to breathe again so naturally my boyfriend was super concerned thinking he hurt me. I’ve never been sexually abused before so I’m really wondering where all this anxiety is coming from??