Messed up bad.

My beaux have 2 kids already so we're not trying for another. I religiously take my bc when it's a possible chance for it not working. We use a condom. But a couple weeks ago we we're trying for a quicky and he didn't put a condom on and he didn't pull out. So now I'm freaking. I put it in my calendar as I'm trying to get pregnant so I know the chances of it but I don't want another child right now. Now I'm sitting here freaking out cuz even when not ovulating there's a chance. Anyone have advice on how to not stress it till I know for sure?