omg. i seriously dont think ecstasy "cancels out" bcp.
otherwise i would be pregnant multiple times over. as would many of my friends. moreover, everyone would talk about it because it would be a REALLY REALLY BIG PROBLEM and everyone would be falling pregnant if they didnt know.
XxmissionBeThYxX - on what basis are you making these "common sense" comments...
if it is so common sense, please back them up with some common sense reasons.
Also, doctors are going to try and get you to stop taking drugs if they can. if she said "its not safe" ....her real reason might have been that it is easy to forget to take your bcp when you are keeping unusual hours and your tired/scattered/going out for days on end/binging for days on end. if it was an explanation such as this, i imagine it would have been convenient to leave the reasons ambiguous.
sglian - as everyone's said period's can come late/stop either temporarily or permanently from stress, poor eating habits and how active you are.
people who are annorexic, for example, often loose their periods until their diet improves or permanently.
its a matter of how far along the spectrum you are in terms of stress and eating etc.
there may be other reasons that im not aware of...im not sure if there are any medical conditions that might have this as a symptom.
so the long and the short of it is you should see a doctor. if you dont want to see your usual gp, go see a new one.