Can I start taking my birth control pills the same day I take plan b? I'm on my period right now and had unprotected sex last night. Do I need plan b?

Yes. Please take the Plan B and the birth control pills. The birth control pills at this point won't prevent this current pregnancy. Also, please don't have unprotected sex even while on the pill. Sexually transmitted infections are rampant in teens, and could cause great harm. Good luck.