You're presented quite a problem list which I'll address as you presented...
Stomach gurgles - this is called borborygymus and indicates the sound of fluid and gas moving through a hypermotile bowel. It's not specific for any one disorder and often is benign.
Shaking - usually a pain response but can also indicate fever, tremors, and seizure.
Anorexia - the causes are legion
Itching - usually due to an allergic dermatitis (flea saliva allergy, atopy/allergies to environmental allergens such as pollens, molds, dust, and dust mites, etc.), food intolerance) but also seen with parasitic, bacterial, yeast, and fungal infections.
Drinks a lot after scratching - I don't know of any correlation between drinking a lot and scratching but drinking a lot at her age is worrisome for chronic renal or hepatic insufficiency, diabetes mellitus, Cushing's disease, urinary tract infection involving the kidneys, electrolyte (sodium, potassium, chloride imbalances), hypercalcemia (increased serum calcium), pyometra (uterine infection) if she hasn't been spayed, and the rarer Addison's disease and diabetes insipidus.
Can you upload a copy of her test results to our conversation? I understand that you might not have a copy at home but her vet can give you one which you can scan into your computer and then give me file link or you can photograph the pages and upload them by using the paperclip icon above your message box (if you can see the icon) or by using an external app such as dropbox.com/ I not only review the test results but also note which tests should have been performed but weren't.