Can Bleeding After The Periods Be Symptom Of Pregnancy?

Hello. Last Friday I started my period while out of town. My boyfriend and I had unprotected sex Saturday night, and ejaculated inside of me. I am not on birth control, but I believe the chances of me being pregnant on my period are very low. I took the Plan B (I think it was called Next Choice?) the next day when I arrived back to town. I'm still on my period, which usually only lasts like 4-5 days. It's not as heavy as my normal period, but there's still blood. Do you think I could still have a chance to get pregnant?