Birth control...should I also take plan B?

I take birth control every day at relatively the same time every day (within an hour) I just finished my period on Sunday 2/11 and started my new pack of BC pills that day, I have taken Sunday, Monday and Tuesday. I had unprotected sex last night (2/13) and bf came inside of me. Should I also take plan B to be safe? Since I still have 3 weeks left until my placebo pills, please help! 😔