Plan B on BC

So, I’ve been on Mononessa for about 6 months now, but I couldn’t get this months refill in time because the pharmacy was closed for 3 days straight. Meaning, I was supposed to have started my new pack last Sunday but I had to wait a week to start it this Sunday. I had been off the pill for that week and my period had ended last Wednesday. My boyfriend and I had sex and he didn’t pull out, even ejaculated twice. Should I get Plan B just to be safe or should Mononessa still be in my system?