Welcome to Justanswer! I am Dr Altman and happy to assist you both today!
So sorry to hear that your dog is showing these symptoms. There are a wide variety of causes of increased water intake in dogs and a first morning urine sample evaluation (collected in a tupperware container, refrigerated if more than an hour old), examination, and bloodwork is warranted to determine the origin or these symptoms.
Differentials for the symptoms include a urinary tract infection (even without overt signs of blood in urine), kidney disease, bladder stones/ crystals, liver issues, endocrine disease such as Cushing's, diabetes. Once diagnostics are done hopefully an answer as far as cause can be determined and appropriate therapy can be initiated but gathering more information is the key to getting her treated and hopefully resolve the symptoms currently experiencing.
The hiding and increased fear can occur with ingestion of something but also if he is not feeling well due to whatever the underlying cause is he will be hypersensitive to his environment. This can be diabetes, cushing's disease, but as you said something that he ingested.
With his symptoms I would not advise waiting it out since there is no resolution in 2 days time. In addition, we are going into the weekend which increases risk of an emergency visit if things escalate. He is really not feeling well and getting answers now versus monitoring and possibly putting his life at risk is not advised.
I hope this information makes sense but please let me know if I can be of any further assistance today. I truly hope he is feeling better soon.
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