New mothers give newborns very much attention, that they also need, but when you have the second child you realize they don't need SO much attention, you don't have the capacities to give them everything, as you have to take care of the other child, so basically you do what you can do, and that's less than with the first child. Unfortunately, there's no way you know it, when you are new mother, you want to do everything right. (please, don't take me literally, I think I'm a good mother, but you don't have to run to the baby at every peep
And yes, it's a hard job to take care of a newborn, although it sleeps so much. You are sleep deprived, tired, you don't know so exactly what to do and the most frustrating thing is when you don't know, why the baby is crying.
But, as somebody pointed it out very well, you have to sort out your priorities. At first the priority is your baby, but after a while it could be you, your body. And as I'm getting older I have to take care of me more, if I want to look good, I sacrifice other things for it - mostly cleaning and gardening

So, it's the priorities