Do you think there's a need for me to get a plan b

Me and my boyfriend were having sex with a condom on of course but towards the end when he was pulling out cause he pulls out any way with or without a condom on we noticed the condom was broken towards the tip I've been on birth control for a week now. Him and I both think I'm fine and that I shouldn't be pregnant but we still don't know if it's necessary to waste $50 and get a plan b do we need it or are we fine since I'm on the pill