possibly pregnant?

Jillian
okay ladies, let's talk pregnancy. 
I had sex December 17th without a condom and without being on any kind of birth control. He pulled out while I was on top and went on this stomach but then I sat back down and he went back in. I had his stuff all over me. My period is due in about 6 days but sometimes I'm irregular. My question to you all is - is there a possibility I could get pregnant or are the chances extremely unlikely? I'm not trying to prevent pregnancy so if it happens I'll be happy. Thank you!