Bleeding after stopping birth control?

Michelle • Baby 💗 born 6/11/17 & 💗 born 8/27/19

I was on Sprintec for only 5 days. I was having some horrible side effects so I stopped taking it. I felt better almost right away but I started bleeding pretty heavily 4 days after I stopped it. Is this normal?? I am 12 weeks PP.. and I’ve had one period since the baby... which was only 2 weeks ago!