Help.

Me and my boyfriend recently had sex two nights ago (on the 5th) and I was supposed to get my period on the 3rd but nothing is happening yet. I get cramps once in a while but no blood is coming out. We stared having unprotected sex and halfway threw he decided to put a condom on. I had been gone for two weeks so it was the first time we did anything since then. I'm scared to be pregnant. What should I do? Please help.