My period should start on March 5th, however I did have unprotected sex about 4 times last month (w/ my boyfriend). My last period started on Feb 5th, unprotected sex 15,16,17, 19 & 27th. I've had cramps for 2 days now, my breast hurt. Could this be a sign of pregnancy or my period starting this weekend? I only ask because my breast never hurt during my period.

Could be. Why not take a pregnancy test to find out?