You should be checking with your vet.

Typically a good vet won't release an animal until they are awake and stable. I would call and talk to the vet, let them know what is going on. They may have advice or have you bring her back in. Sometimes it can take a day or so for their system to set out enough that they want to eat.

Call the vet.

I also think you should take her to the vet. My dog had mammary cancer and had tumors removed. Afterwards she was alert but high on drugs. She didn’t live much past that surgery but had a lot of health issues.

My rat had mammary surgery and she was a hot mess for a little while after her surgery. As my best friend said no one comes out doing amazing after major surgery. Don't stress too much just yet!!

Take her back. Sounds like an infection.

Get her back to the vet immediately

Shoot it.