Parenting a new one is hard, one of the hardest things that humans will do.
The psychological, emotional, and physical demands are as difficult as most anything that we can willingly put ourselves into.
Sometimes the only thing you can do is just hold on. I mean, as Theodore Roosevelt once said:
When you’re at the end of your rope, tie a knot and hold on.
This is all you can really do. The payoff comes much later.