Postpartum blood loss

Mandy
I'm 4 weeks postpartum as of tomorrow. At 3 weeks my flow has lightened enough that I switched to regular pads. The next day I started to bleed and cramp like a period. It's now been a week that it just gushes out. My body is weak and I've been light headed, dizzy, and the chills. Finally I called my doctor and because it was the weekend they told me to go to the ER. I spent 6 hours in the ER for the doctor to tell me that she can't explain what's causing the bleeding and my other pains. Is anyone else experiencing the issues with increased bleeding out of no where??