Had sex 3 days after my period ended, took plan b right away now it feels like im on my period but its just clear thin discharge , should i be concerned ? did the pill worked ?

A slight bit worried: Plan B can alter the menstrual-type 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 3 weeks after sex, because Plan B works most of the time, but not all the time. One can call her primary care doctor to see about any changes in vaginal discharge, to see if an exam is needed.