Super TMI but please give me your input!!!

monika
So I started dating this guy a both three months ago, and the other night we had sex for the first time. 
The sex felt... Really good. But I couldn't get past the fact that while he was inside me it literally made me feel like I had to fart/poop the entire time. Including him, I've been with 5 people and I have NEVER got this sensation before with anyone else. 
We had sex a second time a few days a later and it happened again. 
I am so confused. I tried to go afterwards and before to try and clear anything out and I didn't even have to go. So why is this happening? And only with him?
Could it be that his penis is pushing on my bowels or something?
Has this happened to anyone else? 😭 it's so frustrating and super embarrassing!!! it's  making me unable to even enjoy the sex with him because I'm so concerned that I'm going to poop or fart. Someone give me answers!!! 😭😭😭😭