I had sex on tuesday , on bc and took a plan b for having sex for the first time in 7 months . now my period is late and i had weird yellow discharge

About Plan B...: Plan B 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. If there is a new type of vaginal discharge, her doctor can evaluate to see if there is a vaginal infection needing treatment.