Question about pregnancy, someone knowledgeable please?

On March 5th, I had protected with a condom but there was leakage. At the time, my period was expected to come a few days later. Regardless, even though I shouldn't have been fertile at the time, I took Plan B One Step within two hours of the incident to be on the safe side and got my period 8 days later (last Monday) which was extremely heavy and long... I just finished today, March 21st. However, I am still somewhat nervous about pregnancy. My question is this: let's say I had ovulated on the day of the condom mishap or a few days later and the egg was fertilized. The fact that I just had my period would then mean nothing, correct? Wouldn't I miss my next period if I had gotten pregnant? I know implantation can take up to twelve days after ovulation. Right now it has been 16 days since the accident and because I am no longer on my period, is it possible that a fertilized egg could still implant itself within the next few days?