Possible SA/why didn’t I retaliate

I didn’t want to say it or talk about it out loud but today at school this boy thought it was ok to smack my butt. And idk if he meant to hit me somewhere else or whatever but he most def did. And I’m like wtf but I let it go and just left to next period. But then when we got to chem we was doing notes and then the boy sits behind me and then he gonna smack my *** again. And I turned around and I’m like wtf is wrong with you stop f**king touching me. And then after that idk if I was over reacting but I started to feel real violated cause why tf are you touching me like that. I have never played with you like that. My anxiety was on 100 to the point where I was about to cry and I lowkey felt trapped and dirty and I didn’t slap him or anything like that the only thing on my mind was to get as far away as possible.