I'm up with a newborn too honey while my olders are snoring it away; it will get better. Listen to the rain and breathe.
Before I say anything else, here's a virtual hug

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Do you have a basic schedule set up, one with breaks? This might help get the momentum back up and also give you a bit more balance. If you don't mind me asking, what are the ages, numbers of children that are older than newborn? I'd love to try to unpack the monster of being overwhelmed with you.