Exs but friends who have amazing sex? HELP! 😫

I have sex only with one guy! He and i dated for over 1 year, close to 2 years! We saw each other at the club last week, and he got drunk so i didnt fell comfortable letting him drive back home, so i drove him home. What I wasn't expecting was to have AMAZING BOOM sex! Now im just sooo confused because im not sure where our "friendship" stands, he says nothing has changed, but he doesn't know im late, like 4 days late.. What do i do ladies! Im hoping im just late, but should i let him know or should i wait?