Hello, my name isXXXXX and I have over 20 years of experience as a veterinarian.
I am sorry to hear that Satin has lost her appetite, isn't drinking and is vomiting and I'd like to help. I agree that even if they could not find anything on exam and basic blood tests were normal she obviously isn't if she won't eat and continues vomiting.
Vomiting can be related to chronic pancreatitis, esophageal reflux, a dietary allergy or sensitivity, toxin exposure, a viral or bacterial infection, inflammatory bowel disease, heartworm disease, hyperthyroidism (a tumor of the thyroid gland) internal organ failure, a full or partial gastrointestinal obstruction or even infiltrative cancers such as lymphoma.
Because she isn't eating or drinking and continues to vomit I am very concerned about her. She will quickly become dehydrated and as her liver breaks down fats for energy to live she may develop a type of liver disease called hepatic lipidosis.
If she goes outdoors exposure to infections, toxins and eating things she should not are real concerns.
If she is indoors only then internal organ disease, including pancreatitis, liver and kidney disease or even infiltrative intestinal disease or tumors are more likely.
I am glad to see that she saw a veterinarian and that they ran blood tests. Do you know what they were and did they take radiographs and/or perform an ultrasound to evaluate her?
If basic blood tests were normal then more specific tests such as a feline specific pancreatic lipase (fel specPL), a heartworm test or an abdominal ultrasound may be more diagnostic.
In the meantime they can administer injectable anti-nausea drugs and fluids to rehydrate her.
Until you can have her seen there are some things you can try at home.
At home to try and settle her stomach and stop her vomiting you can give either:
1) Pepcid ac (famotidine) at ¼ of a 10mg tablet per 5 to 10 pounds of body weight every 12 hours
2) Prilosec (omeprazole) at ¼ of a 10mg tablet per 5 to 10 pounds of body weight every 24 hours
These are acid reducers and should help her feel better.
If she stops vomiting you can use a medicine syringe to try and force water into her orally.
I also recommend feeding soft foods mixed with water to make eating and swallowing more comfortable.
If she is refusing to eat even soft foods you can try offering meat baby foods or a bland diet of 2/3 boiled minced white skinless chicken and 1/3 boiled white rice mixed with some low salt chicken broth to make it easy to lap up and swallow.
If she continues to not eat she should see a veterinarian for another examination, diagnostics and intravenous fluids and supportive care.
Please let me know if you have any further questions.