It can stop and start, but if it fully stopped for that long, it's definitely your cycle picking back up (which can be funky for a while!). Language is important when taking about stuff like this. It isn't SHOULD* last. It is "postpartum bleeding MAY** last UP TO** 6 weeks. Your 3 weeks is totally normal and healthy. I breastfeed my babies, and my PP bleeding is always done by 2/3 weeks and my cycle usually comes back my the 6th week, too. It just means your hormones are balancing out and going back to normal quickly - which is a good thing!
C section mama here ! I BF & pump & also bottle feed. My bleeding stopped about in 3rd week. And I just started bleeding like period again on my 7th week ! 😊
i bled for maybe 2 ish weeks after giving birth and then it stopped but came back around 5-6 weeks and maybe lasted barley a week it’s completely normal but if ur bleeding through a pad every hour or so go see ur doctor or the er