How long after giving birth does your menstrual cycle take to go back to normal?

[Johanna]

Hi I had a beautiful baby boy three months ago, I did not have any pregnancy complications and I had a normal delivery also I am not breast feeding. After I had the baby I bled for four weeks which is normal than stopped. Since than I have a period every two weeks. It starts out light with what seems to be old blood because it is very dark than it turns the normal red color and becomes very heavy for about five days straight and just stops, than two weeks later the process starts all over again. It is so heavy I use a Super tampon in one hour. The first couple times this happened I went to the emergency room and the doctor told me my body was just going back to normal and it could take a couple more weeks but it has been three months and it is still happening. I have asked several people I know if this seems normal but everyone I know says it's not. I made a doctors appointment but it is not for another two weeks. Also when I am on my period I feel very weak and drained, I sleep a lot and if I do not get enough sleep I am very moody for the whole day. I have not started taking any new birth control and I have not been stressed lately. My periods have been normal my whole life until I had my son. Does anyone have any ideas of what this could possibly be and if I need to be worried? Anything helps!