Welcome to Healthcare Magic.
It seems you have started the birth control pill on the day of sexual exposure to avoid the pregnancy
The oral contraceptive pills
need time to act and are not effective if started in emergency.
They must be taken regularly every day for 21 days followed by drug free week.
If you are within 72 hours of the exposure you may start another type of medicines called Emergency contraceptive kit.
I hope the advise will be helpful for you.