Will The Next Period Come In The Following Month?

My period was a week late (I hadn't had sex in a while so I know I wasn't pregnant, I think it was just stress) then midway through my late period I had unprotected sex where the guy didn't ejaculate inside but pulled out. I got Plan B about 36 hours after this occurred. If I had already skipped my period I shouldn't expect to get it until my next go around, correct?