Period like cramps 1-2 weeks before period?

Lindsay
This never happens to me. I hardly ever even cramp for my periods. My fiancé and I had a slip up and he came inside of me a day before the ovulation (green days). I noticed and went and got a Plan B pill the next day. My period is supposed to be here tomorrow. I am going to get a test tomorrow but what are the chances this could mean I'm pregnant?