I had unprotected sex while ovulating and took the morning after pill 3 days later. is there a chance the morning after pill isn't effective?

Morning after pill: the morning after pill is very effective fu to 72 hrs after sex and moderately effective for 120hours

5 4 3 2 1: Its effective up to 5 days. Every day, there is less of a chance it will work but for 5 days it is still worth the money to use it for its purpose. Also purchase pregnancy tests. Have your prescriber prescribe another morning after pill for future emergency use (this way you can use a coupon or insurance can make them cheaper.

Not 100% effective: Emergency contraceptive such as Plan B One-Step are up to 89 % effective when taken within 72 hours (3 days) after unprotected sex. It can reduce chance of pregnancy by up to 95% if used within 24 hours. It continues to reduce the risk of pregnancy up to 120 hours (5 days) after unprotected sex, but is less effective as time passes.