I'm on lo loestrine fe and i had the same problem; The first month i was on it i bled even before taking the last active (white) pill, and bled for a long time (probably because i started taking it right before i was supposed to get a period). Anyway, was on it for three months after that and never got my period again. i haven't taken it in about a week (ran out) and still nothing. I was also scared that i was pregnant but i took a test and it was negative. My sister is on the same pill and she said she almost never gets hers. i think you're probably fine, but take a test if you're really paranoid - it's the only thing that will ease your mind.