DEPO SHOT AND LATE PERIOD... HELP!

I took a depo shot in April and decided not to re take it. Since I wouldn't be sexually active and it didn't seem to be the right BC for me. August was the first month off the BC and my period is late... Like really late. Which wasn't unusual for me, before BC I would skip months at a time.  I had protected sex last week. So anyway my question is, I'm not pregnant right? Is it normal for my period to be so late?