He kind of forced me

So i was having sex with my « friend » who’s also my ex boyfriend. We’ve been together for 4 years, but now it’s just sex. Yesterday we were having sex and he was playing with my ass, and he put his dick inside my ass without even asking me ... when i told him that i don’t wanna do anal, he said « looks like you don’t have a choice.. »! Now i’m at home, crying and i feel like shit. I didn’t know what to do... i’m mad at me for letting him do it..