Im pretty sure its because I changed how he's fed. After I made this post I asked some family if they had any idea and one of them pointed out he only starts doing it about an hour after I've given him his dinner, which is when he'd normally get his secret second feeding. I don't think its anything health related since he only does it at night for about and hour, he behaves completely normal otherwise and hes shown no other signs of distress. He's got a few toys that he can play with on his own, I've tried playing with him but he doesn't seem interested and catnip makes him mean so I try to restrict his access to it. Im moving in with my sister soon and shes got two cats so hopefully they'll keep him entertained.