I usually get my period about every 21-22 days. This time it came at 19 days and started very very light. I'm now going onto my 6th day, which is atypical for me because my periods usually last just 3-4 days and are usually quite heavy for 2 of those days. I also typically get a lot of cramping for a couple days. So far, my period has been a steady but light flow and I've had virtually no cramping. I have begun exercising intensely on a daily basis. Could that be why this is happening?