Very interesting! The only time my period was irregular was when i was 13 and first got them. I had to go on the pill to fix them cos they were extremely heavy and lasted at least 2wks but after going on the pill my period would arrive like clock work (was only on pill for 3moths) then went on the pill again at 15 or 16 to clear up acne and that was for 4 months then went on pill over 2yrs ago after i had my son and whenever its been time for a period on the pill its always arrived on time, and like i said in my first post if i miss a pill or two ill start to bleed so it really has me stumped whats going on!