Why haven't I gotten my period?

Okay so I'm very terrified right now,I haven't gotten my period and the last time I recently had it was on May 23rd. Yes I was sexually active,Didn't use protection ONE time and my bf was sure he didn't *** inside me. But you never know???? Well my periods have never came on the exact same day as the month before,every time i'd get my period I'd get it like up to a week later than the month before. I haven't gotten my period this month and I'm scared. What should I do? Am I pregnant?