He came....help

A couple weeks ago. I had my boyfriend over. We had sex but it was anal. He came in me and I freaked out. I made sure it didn't come out. I rushed to the bathroom and tried to get everything out. But I'm afraid some got on the outside of my vagina. Could I be pregnant? I've been on BC for about 5 months now but the past month I've been forgetting a lot but I'd double up the next day always. Please help me...I start my period in 2 days eve says....