Hello, unprotected sexual intercourse atthe time of periods will have negligible chance of getting
pregnant, (unclean sexual intercourse may predispose you to reproductive tract infections at this time) and taking unwanted 72 with in 24hours of unprotected sex will have 95% of not getting you pregnant. And since she got menstrual bleeding after taking unwanted 72 then don't worry chances of pregnancy is nill. And her weakness is due to worrying and bleeding due to pill, her next period may delay , she will become normal in couple of weeks. Don't worry she is not pregnant.