Hello, my name is ***** ***** I have over 20 years of experience as a veterinarian. I understand that you are concerned about Boo Boo.
Symptoms of bloat (gastric dilatation with or without volvulus or twisting of the stomach axis) may include restlessness, a tight, rapidly increasing in size abdomen filled with gas, unproductive episodes of attempted vomiting, pacing, panting and sudden death.
These pups aren't able to burp, the gas stays in the stomach causing it to stretch and expand quickly.
Bloat is most commonly seen is large, deep chested dogs such as German Shepherds, Rottweilers, Greyhounds Great Danes, and Labrador or Golden Retrievers. While theoretically it could be possible in any dog I have never seen it in a small breed dog.
While it sounds like your pup is uncomfortable and nauseous given her vomiting even water, and decreased appetite and drinking, she doesn't sound like she is experiencing bloat.
She is likely dehydrated because he has been vomiting, but if even water is making her vomit you need to take it away from her for now.
In most cases vomiting is triggered by eating something they should not, too much table food, too many treats or something they find outdoors.
More serious causes of vomiting include toxin ingestions, viral or bacterial infections, esophageal reflux, a dietary allergy or sensitivity, inflammatory bowel disease, internal organ failure (kidney or liver disease), or a full or partial gastrointestinal obstruction. Since she is a middle aged girl then an abdominal mass is also a possible cause. If she has not been spayed and she's recently finished a heat cycle then I would worry about a uterine infection (pyometra).
Because she is so weak and is vomiting even water ideally she would see a veterinarian now.
If that isn't possible for whatever reason there are some things we can try at home, but if she's not improving quickly she should see a veterinarian for an examination, some diagnostic testing, intravenous fluids and injectable medication to settle her stomach.
To try and settle her stomach you can give either:
1) Pepcid ac (famotidine) at one 10mg tablet per 20 to 40 pounds of body weight every 12 hours
2) Prilosec (omeprazole) at one half of a 20mg tablet per 20 to 40 pounds of body weight every 24 hours
These are acid reducers and may help settle her stomach and get her feeling better and hopefully get her appetite back. These can be given for several days if necessary.
I would pick up all food for now and water for a couple hours to allow her stomach to settle after the acid reducers.
In a couple hours when you give her water make sure it is in small amounts only. If she drinks too much too quickly that can lead to vomiting. You can also offer ice cubes to lick. To get some electrolytes in you can offer her a 50:50 mix of pedialyte and water.
If there is no vomiting for 12 hours offer a bland diet of 1/3 boiled, minced, white skinless chicken or boiled, lean hamburger 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 refuses that you can offer a little meat baby food. If she refuses both then don't push it, she needs hands on veterinary care.
But if things go well and she does eat and doesn't vomit feed her the bland diet for 2 to 3 days then slowly start to mix back in her regular food, a little more at each meal. It should take about 5 to 7 days to slowly convert her back to her regular diet.
If she continues to vomit even with the acid reducers, runs a fever (more than 103F rectally), or has a lower then normal temperature (less then 99F), has a tense painful belly or if she refuses to eat she should see a veterinarian for an examination, diagnostics, injectable anti-nausea drugs intravenous fluids and supportive care.
Please let me know if you have any further questions.