Does Plan B prevent implantation?

So I met this guy at a house party in college and we have been on and off hooking up for a year and a couple nights ago we had unprotected sex and he didn’t pull out quick enough and usually I wouldn’t be worried but I stopped my birth control and I was ovulating that day (I track it) I didn’t get to take a plan B till over 12 hrs after cuz I had to drive to 3 stores for one and we slept in... with that being said I know the main purpose of plan B is to delay ovulation but I was already ovulating so does it still work? What are my odds of being pregnant?