Hello, my name is***** and I have over 20 years of experience as a veterinarian. I'm sorry to hear that your girl Josie isn't feeling well and is refusing to eat for the past 3 days, whimpers when picked up and is very lethargic.
Whimpering can indicate nausea or abdominal pain.
Lack of an appetite can be related to eating something she should not have, too many treats or table food, eating foreign material (which could cause a full or partial gastrointestinal obstruction), chronic pancreatitis, esophageal reflux, a dietary allergy or sensitivity, toxin exposure, a viral or bacterial infection, inflammatory bowel disease, internal organ failure, or even infiltrative cancers such as lymphoma. If she is not spayed and has had a heat within the past couple months a uterine infection (pyometra) would also be a possible cause.
Because she hasn't eaten normally in several days even though she is drinking I am very concerned about her. If she isn't drinking enough to compensate for fluids normally taken in as part of her food she will quickly become dehydrated.
Ideally she would see a veterinarian today since this has been going on for more than 72 hours. Simple stomach upset should pass within 24 to 48 hours. They could examine her, run blood tests and possibly check radiographs and/or an ultrasound to evaluate her and know best how to treat her.
In the meantime they can administer injectable anti-nausea drugs, an appetite stimulant and fluids to rehydrate her.
If you cannot have her seen today for whatever reason there are some things you can try at home.
At home to try and settle her stomach you can give either:
1) Pepcid ac (famotidine) at a dose of ¼ of a 10mg tablet per 5 to 10 pounds of body weight every 12 hours
2) Prilosec (omeprazole) at a dose of ¼ of a 10mg tablet per 5 to 10 pounds of body weight every 24 hours
These are acid reducers and may help her feel less nauseous so that she will eat. They are quite safe and can be used for several days if necessary.
You can use a medicine syringe to try and force pedialyte or broth into her orally.
A couple of hours after giving the acid reducer I recommend offering meat baby foods or a bland diet mix of 1/3 boiled, minced, white, skinless chicken or very lean boiled, ground beef and 2/3 boiled white rice mixed with some low salt chicken or beef broth to make it easy to lap up and swallow.
If she continues to not eat she should see her veterinarian for an examination, diagnostics and intravenous fluids and supportive care.
Please let me know if you have any further questions.