Your faith in yourself is all you will ever have. Don't let anyone take it away from you, ever.
When you become a mom you just learn how to function sleep deprived and you do get used to it. I came back to work when Finley was three months old and the first few months were rough. Then somehow you learn to exist on no sleep and now when he does upon occasion sleep through the night, which is like a full six hours, you're pretty sure he's suffocating. So you don't sleep anyway.