I'm a bit late to this but: silly games win silly prizes. If you choose to have sex with someone despite not really wanting to you're going to have to handle your feelings after the fact. You can't transfer blame to him. If you actually did take some kind of action and approach the school or the police eventually you'll be marked as crying wolf and that's not good for anyone, including actual victims of sexual assault. Even worse, someone with a warped view of what actually constitutes sexual assault might take up your cause and amplify it and that's bad for you, bad for him and bad for society.

It also sounds like you feel threatened by him but going by your description you have absolutely nothing to feel threatened about. It sounds like you had sex with a guy who then wanted to be validated as a worthwhile person to know socially, which is what people do after they've had sex. Instead you've gone totally cold on him and dropped him then acted hostile. That's a shitty feeling to experience, nobody wants to find out they've fucked a psycho who acts like that. You have absolutely over-reacted in that regard and it's the female equivalent of a guy being physically threatening, because as you said, you could fuck his shit up in an unimaginably bad way. So to summarise: you regret having sex and so you might fuck his shit up. How does that sound to you?

My advice, if it's still a sore point for you, is to act like a fucking normal person. Tell him it's cool, it's in the past, sorry for any drama, you weren't in a good head space but it's not his fault and not to worry. It would remove any lingering awkwardness and take away the constant threat of some sort of retaliation hanging over his head and at least halts your fairly obvious manipulation of the situation into some kind of dire negative. If he does do anything stupid after that (because let's face it, you're both in college) then it's on him. But try to keep in mind that you also did something stupid and that it's OK to give people a pass. Dramatising small things is a really ugly personality trait and not one you want to develop further.

Make better choices and handle the wrong ones that you do make better. Harden up and accept that you put yourself into this situation and you'll have to bear the burden of it for a while. Own it. Everyone's been there. You'll feel better once you realise that taking responsibility rather than deflecting it solves things instead of turning them into bigger problems like what you've already done.