I will go awhile without getting my period. When I do get it, it will last for a very long time (a few weeks to over a month). During the middle/end of the period my flow will become very heavy and I will often find large clots in my menstrul blood. The clots are very frequent during this time (the clotting can last a couple of days or even a whole week in itself). I am overweight and have been trying to lose weight and no matter how much I exercise and how well I watch my diet, nothing happens.