The only thing worse than every day being completely different is every day being exactly the same.
We're in completely different territory now. There is no routine. Every single activity has to be managed on the fly. Meals, showers, trips to the bathroom. It takes up enormous mental and physical effort. But, if I recall correctly, there is a long period with a new baby (or two), where you do get into a routine. The problem is that the routine takes up 98% of your time and bores you to death. Luckily, that doesn't last forever either.