I took a plan b pill two days after. A week later I came on my period for only 3 days instead of the full seven.

Me and my boyfriend had unprotected sex to days after a seven day long period. I took a plan b pill two days after a week later I came on my period for only 3 days instead of the full seven. I have taken plan b before but I always stay on my period another seven days could I be pregnant.