Had sex directly after period on Birth Control is my girlfriend pregnant?

Hi,

My girlfriend has been on Birth Control pill for the past two years and we have unprotected sex. She finished her period on friday but didn't start taking her pill this month untill sunday night. We had unprotected sex one hour after she started the pill again. Was she too late in taking the pill? Were we too quick in having sex after beginning the pill cycle again? What is the possibility that she is pregant? Should we take a morning after pill?

Thanks