my last period was in october after my bday. my usual 4 days (Oct 3 to the 6). my period suppose to start November 4th. nothing. when i go to the bathroom all this month. i been seeing brown blood and every now and then red blood but mostly brown. i have been sexually active with my fiancee. i haven't had any pregnancy symptoms. i know i been moody every now and then and i took a pregnancy test on the 11th and it was negative. i been my normal self and i havent been stressed... what could it possibility be?