Thanks for the query to ATD for an opinion,
If the plan b was taken within an hour though you may be on day 10-11 of your cycle ( onset of fertile period), still plan b when taken within 72 hrs of last intercourse has a success rate of 99%.
The withdrawal bleeding following plan-b should start in next 5-7 days and once it arrives it shall indirectly confirm that you are not pregnant at all as all the endometrium shall be shed and implantation shall be prevented.
I hope i have answered your query in detail,
Wishing you safe sexual practices,
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.