Taking a Plan B on day 14?

The only emergency contraceptive pill that is proven can prevent pregnancy, during the 24 hours around ovulation itself, is Ella (Ulipristal Acetate), & even that is not guaranteed if you're already ovulating (you can see this on the Ella website). Plan B might help, but it has not been proven.

In the situation where you have an emergency when ovulating, you can try Plan B if you cannot get Ella, but I would also suggest having a Paragard IUD fitted by a doctor, within 5 days/120 hours of the unprotected sex, which may stop a pregnancy implanting, if the emergency contraceptive pill does not work.

Not everyone becomes pregnant from having unprotected sex during ovulation, but it is the time that pregnancy is most likely to occur.