Is there a possibility that I could be pregnant?

Christine
I'm due for my period tomorrow, so I haven't missed my period yet, but I was wondering if I could still get pregnant if I had unprotected sex a few times this past month. He always pulled out, never finished in me. Paranoid as I was, I did take plan B after one of the times we did that. I've been feeling kinda funny starting yesterday--mild cramps, nausea. No spotting, no breast pain...
What are the chances of me being pregnant? I would really appreciate nice comments please.