It sounds a lot like Canine
parvovirus, which is dangerous and fatal.
When it comes to
parvovirus there are a number of symptoms to look out for. The disease makes it impossible for the dog to absorb liquids and nutrients and as a result, the dog will suffer from diarrhea and may also experience lethargy and vomiting. There is a loss of appetite. Most dogs stop eating and have particularly foul smelling and bloody, liquid stool.