Pregnant?

I am worried that I could be possibly pregnant. Recently, I went to visit my boyfriend and we engaged in sexual intercourse. However, I made sure ahead of time that I was not ovulating, (which I wasn't). All of my six calendars informed me my ovulation had passed. We used a condom, except we had 15 seconds of unprotected sex. My boyfriend did not cum and he has low fertility. However, my period isn't here yet, but then again my schedules are irregular. Is there any chance I am pregnant or is it all in my head and am I allowing the stress to get to me?