I have had this happen to me already twice in since Sept. 2011. I had ended my period at the end of Sept, then had no period until 12/31. It lasted over a month, and most of it was very heavy bleeding. I saw my OB and he ruled out pre-menopausal and found no physical evidence of anything. Ordered an ultrasound and he believes there may be a cyst in my ovaries (?). Anyways, he reassured by period would end in a few days and explained that me having a heavy period was because I did not have one for 3 months. Mind you, I have never been late (other than when I was pregnant before) and never been late like this. Now I ended my period in early Feb, but yeah, I have not had one since then. My doctor ordered meds to get me to start, but it did not work, so we are looking at surgery in my uterus.