he hit me

i’m posting this anonymously because i don’t want to be judged, but from the title you can see that my boyfriend hit me.. i just need some advice from guys because i know girls on this app will tell me to leave him.

so i’m 16, he’s 17 i’m a cheerleader and he’s a football player at school. recently he did something to his ACL (i don’t remember exactly) but he hasn’t been playing for a while and it’s been making him upset seeing all his friends playing when he can’t (he comes to games to support me). he’s been really on edge lately and while we were arguing he got mad and slapped me. we’ve been together for 2 years and hes never ever done this before so i just put it down to stress. i’m worried that his injury is affecting his mental health in a bad way and i’m not sure what to do? i feel really helpless because i know he’s hurting and there’s nothing i can do to fix that. he’s worked super hard for his body and gained so much attention and popularity and i feel horrible for him. what do i do?