The most obvious causes
for your dog's symptoms include:Giardia, Pancreatitis, HGE, IBD, Parvo, and stress colitis. Another possibility is a GI foreign body (The GI foreign body would
require a barium study and possibly surgical removal of the object). There are snap tests for giardia, pancreatitis and parvovirus that
can be performed in-house immediately.
These diseases, except a GI foreign body require symptomatic therapy at the vet's office.