blood clots

4 wks pp I'm currently on a pill for bc but i haven't taken it for 2 days(u have to take it everyday at the same time. i started my peeiod 2 days ago. its lots of huge blood clots(bigger than a quarter) the blood is dark red. when i wipe myself even more blood clots come out. changing my pad every hour and a half to 2 hours. this is my 3rd baby but i dont remember all this blood coming out like this. i did have a c section this time.