My Period Had Stopped For The Better Part Of 5

My period had stopped for the better part of 5 years, then recently I had a very heavy period for over a week. I was losing large clots, for six of those days and bleeding was extremely heavy. I had an episode suchlike this approximately eight years ago and was told that the lining of my uterus was shedding. Was this more "shedding" and hopefully the end of it? or was it cause for concern?