birth control & plan b

hi guys, I just started my first pack of sprintec on Jan 19 (the first day of my last period) and I’m now on the last two days of my placebo pills. Last night my bf accidentally did not pull out and I’m wondering if I should get a plan b. I take all my pills at 9:30-10 every night and I’m just stressed bc this is my first pack and I don’t know if it’s in full affect. Mind you this happened while I was bleeding too on the placebos. Thanks