my last regular period was on 15 of aug..i had sex on 7/09/2014,(unprotected)... and again on 19th of the same month... my bf is pretty sure he didnt come... i had a short light bleeding from 27-29... the we had the sex again on 17/10/2014... and i had taken ipill at 33hrs..i had the bleeding as told after taking ipill... we had around 6 pregnancy tests taken up in a span of 2 months ie.. from sept- nov... and all are "NEGATIVE"... but on 1/12/14... i had brown spotting on my undies wen i woke up in the morning... am freaking out ... plz help... am i pregnant or are my periods acting late ... i have constipation and no other symptoms ... plz plz plz HELP!!!