They are sensitive little souls, and pick up on ambient anxiety in their humans.
Years ago, during the "Chinese melamine in the pet food" disaster I was dealing with three older/special needs kitties. My vet gave me a recipe for making cat food, and I used to make it up for them fresh every day. I will scout around to see if I can find it. It does involve getting some vitamins, etc., to add to it, but it was primarily chicken-based, if memory serves.
I think it's on the old computer. Which I brought with me but never set up. Will try to fire it up and pull that recipe off if I can find it, and post it here. For dogs you cut down the protein ratio - add oatmeal. (Cat food is generally too protein-rich for dogs, because cats are obligate carnivores and dogs are not. I think.)