could I be pregnant?

My last period ended on December 10... and on that day my bf came in me, so taking precautions I took plan b the next day... I should've got my period already by Jan 1 or 2. But it's late 11 days now, and I know plan b does make your period late, I have been getting period like symptoms but no period yet. Am I freaking out for nothing or should I get a PT???