Does antibiotics cause period to stop? i took it on first day of periods, the very next day bleeding stopped. 10 days before period i took ecps too

Emerg Contraception?: Plan B and other emergency contraceptive pills can alter the menstrual bleeding for the cycle in which Plan B was taken, and sometimes the next cycle too. One should be sure to check a home pregnancy test about 3 weeks after sex, because Plan B works most of the time, but not all the time. Antibiotics are normally not expected to alter one's menstrual bleeding.