I had unprotected sex last Saturday and took Plan B on Sunday. I tested my ovulation today (Wednesday after) and it says high fertility. Should that be? Also, how many days does Plan B protect you, because I stupidly had unprotected sex Tuesday. I monitor my fertility as I'm trying to get pregnant, however this was a bad time of the month, because I underwent several tests to screen for breast cancer. I understand, you shouldn't get mammograms if you are trying to conceive, but during your period as it can damage the egg.