Just got back after 2 hours at the vet with Sassy. She has lost 2 pounds from not eating

Seems she has had an anesthesia reaction and that combined with the pain medication caused issues. She was badly dehydrated so the gave her subcutaneous fluids, 2 injections for nausea and to stimulate her digestive system, and a full panel of bloodwork which all came back normal. THANK GOODNESS!
I feel so bad for her

They want me to try and feed her in a few hours...hoping she eats something