Did I over react??!

Soooo me and my boyfriend were at a friends party about a year ago ad everyone was drinking and enjoying ourselves as you do.. I was in a different room on the couch trying to sleep and my boyfriend in the room next to me with others, I over heard him talking to a girl he knew saying how amazing she was and that all the boys thought she was "class looking" I confronted him next day and was so angry and hurt I broke up with him 😩 we got back 4 weeks later after sorting things out and have been together ever since.

Last night we were at his sisters birthday party the girl was there who he was chatting up that night😪 she kept dancing and bumping into him trying to get his attention probly. I also kept catching him looking at her the whole night and my blood is boiling 😡😡.. so we got home and it started a whole argument I got so angry I slapped him on the face and told him to never talk to me again, I haven't stopped crying since and I'm deeply hurt😪 I'm 8 months pregnant also! Am I overreacting or is it my hormones??!