I'm scared

Hey. I'm 18 years old and this Saturday I went to a party with my boyfriend. We had sex, and in the third round I told him to go in without a condom as long as he pulled out on time (I was drunk and it was the heat of the moment). He pulled out and everything, but my period's late one day and I am paranoic as hell. I take the pill and my friend told me it could be late because I am stressing over it and I could end up fooling my body.