Oh man, so glad to find this thread because I was getting ready to ask about this. I've never had normal periods - they were irregular and fairly rare and lasted forever. I always assumed it was because I was overweight, because if for some reason I didn't eat much for a few days, it would arrive. Since I started low carbing, I seem to have it all the time! Thanks to all for making me not feel like a freak and thanks to Nat for the info re estrogen - I didn't know that and it explains a lot.