If my ovulation date was nov 16 and i had sex tgat day abd took plan b that day could i be pregnant?

Possible: If you take it within 72 hours after you've had unprotected sex, Plan B can reduce the risk of pregnancy by up to 89%. If you take Plan B within 24 hours, it is about 95% effective. But you should know that Plan B or Plan B one-step is not as effective as regular contraception. So get on regular birth control to prevent pregnancy and do not rely on plan b.