Sorry I was gone awhile; I had a power failure here.
These symptoms could indicate pain somewhere ( his back, or internal organs). The drooling can indicate nausea, pain, irritation in his mouth, or internal organ disease.
Good that he is drinking, and staying hydrated. Is he eating?
If I could, I would start with a complete exam: take his temperature, feel his lymph nodes and internal organs, listen to his heart and lungs, check his gums, hydration, and feel his legs
and back for areas of tension that can indicate muscle
spasm, or pain.
Could he have gotten into anything?
I am worried he may be in need of medical attention. Until you can have him examined by a veterinarian, I would try to keep him quiet, and keep him drinking liquids. You could see if some Pepcid AC (famotidine
) helps with the drooling: 10 mg per 20 to 40 pounds of body weight.
Let me know how he is doing and what else I can answer or help with.