I am 19 yrs old and i had unprotected sex on 11/27/11 around 4am where my partner ejaculate inside me. On 11/28/11 i took the Plan B pill One Step at about 3pm. On Dec 5 i got my period, with light cramps that lasted five days, and i believe that was due to the pill. My normal period was due on the 12/17/2011 but i am usually a couple days late because i have irregular period. Now Today,Dec 20, i started having brown discharge, stomach pain, and light cramps. Could that be the beginning of my periods or implantation bleeding? I can't take a PT now since am having this discharge so please help! Thanks.