Hi, it looks like your cat is being treated for a bacterial infection. Did the vet tell you what the source of the infection is? If your cat doesnt start eating you are going to have a lot more trouble ahead. Have you tried feeding a really good canned food? Try Tiki Cat wet food in different flavors. My vet recommended this for one of my senior cats that wasn't eating properly and was turning down everything I put in front of her. She ate the Tiki like no tomorrow and is doing fine now. I feed all my cats Tiki now. Anyway, you need natural food that is high in moisture to prevent dehydration and flush out the bacteria from the system. As soon as your cat is off the meds, be sure to get a probiotic in the food to replace all the beneficial bacteria that will be killed with this treatment. I wish the best for your kitty and you.
My vet told me that if any of my cats went without eating for 24 straight hours to bring them in. Sometimes they can give them stuff to stimulate their eating. I sometimes open a can of tuna(water not salt) and just take the water stuff and put it on the food. But please take your cat back to the vet or find another vet.
I don't have anything helpful to add...but I wanted to say that I'm sorry your little friend isn't doing very well.
There are lots of really helpful people here...and a great place to make friends. I saw your other post that you are 88 and divorced - you are in good company here with lots of gentle souls - all glad for some company!