anal on accident

I seriously don't see how y'all can do anal!!! For the first time i did it but it didn't happen how you think it did. We were having sex and his dick slipped out and he put it back in without his hands and it went in my ass! He had me bent over the bed, with his chest on my back and some how he didn't know it was going into my ass. I screamed at the top of my fuckin lungs and I cried uncontrollably and dropped to the floor. Yes I was super wet so his dick was in went in easily but the penetration bout made my soul leave my body. When I screamed he grabbed me and asked me what was wrong because he knows I don't do that when we are having sex. I never wished his dick was little until that happened. I am traumatized and I will never ever have anal.