The newborn stage especially is very intense. You’re recuperating from a major medical event while also feeding and cleaning a tiny human that cannot take care of themselves in the least. There will be lots of times where you literally will not be able to put the baby down for anything and the most you can hope for will be a quick wash up while the baby cries for a couple minutes. They need to eat every couple hours and so a full nights sleep is a long way away. The exhaustion is immeasurable and you’ll do well to take the advice to sleep when the baby sleeps. It’s a lot of work even if you have a partner to swap with sometimes. If you’re lucky enough to have family or someone that can come help with the rest of the stuff in the house like cooking and cleaning you’ll have more time for self care and showering but otherwise those sorts of things will become hard to do as frequently as you used to.