Condom fell off

Was having sex tonight (Monday) and at one point we realized the condom fell off inside me. I am not on any other form of birth control. He got the condom out of me and said he hadn’t finished yet. So he put on another condom and we kept going.

According to my apps (I use two of them) I either ovulated on Friday or Sunday, so my fertile window either ended Saturday or today, Monday. I think the app with the Friday/Saturday prediction is usually more accurate.

I have an expired plan b on hand, but I most likely already ovulated, and I weigh about 190lbs - all factors that will make it less effective. He didn’t finish before the condom fell off, but I’m worried about any precum that might’ve happened. But I also don’t want to deal with the side effects of plan b.

What would you do?

A. Take the expired plan b

B. Get a new plan b

C. Nothing