Some cats have a little or a lot of separation anxiety. There are things you can do to help calm and/or appease them (while lessening your own guilt for leaving them). Those sad eyes get me every time when Lily knows I’m going to travel someplace. She gets in my suitcase and gives me the sad eye-treatment. Some cats act out—cause some sort of problem when her human is gone.
What can you do when your cat seems to suffer from separation anxiety? Get her a companion cat. Leave an item of your recently-worn clothing on the bed or their favorite chair. Turn on the radio or TV while you’re gone. Have someone come in and spend time with her each day while you’re gone. Have your pet sitter keep to your routine as much as possible—feed at the same time, for example and in the same place the cats are used to being fed.
Here’s a great article from a cat behaviorist that should be helpful. http://www.catbehaviorassociates.com/separation-anxiety-in-cats/