Please help! Postpartum bleeding

I had my son 5 weeks ago. I stopped bleeding at 2 weeks postpartum. Now all the sudden I’m bleeding HEAVILY. I haven’t had sex yet. The bleeding started all of the sudden and is very heavy. Small clots too. Called the dr and I’ve been waiting 4 hours for a call back. I don’t think it’s my period. I’m breastfeeding and have no cramps or pain. I’ve been bleeding now for 3 days and it hasn’t gotten any lighter. Really concerned.