Is it normal?

I'm 7 weeks postpartum and had light bleeding. I didn't stop bleeding but 2 days ago started bleeding heavy like my period usually is. The doctor didn't seem concerned the other day but I also found out they put me on a progesterone only (I think that's what she called it) birth control pill. They had me on a vaginal progesterone while pregnant but that's the last I heard about progesterone. Could it be from the birth control, period or what? I only had 2-3 weeks of light bleeding after my first, got my period a couple weeks later but wasn't on any type of birth control then.