He Didn't Pull Out!!!

Ali
Soooo I'm on both control for 1.5 months and my body is still getting used to it. My boyfriend didn't know you have to wait 3 months and he finished inside me last night. I was going to take plan b the next morning, but I just got my period/spotting. 
-Should I take plan b? 
-Should I keep taking my birth control normally if I take plan b?