My Jesse was extremely sick two weeks ago with what the vet diagnosed as HGE and said there was no known cause, but boy it sure sounds similar to this. He started out with vomiting and rapidly went downhill with bloody diarrhea and then just blood and extreme lethargy. I got him to the vet the first day before he was extremely ill and they gave him metro and some subq fluids and sent him home. After he became very ill overnight, I took him back and they kept him for the day and gave him IV fluids with antibiotics. He was still very ill for several days, but slowly got better. He wouldn't eat so they gave me some appetite stimulant for him and some special food. He was also on Meto, Sulfacrate, and Cerenia. His poops are still not back to normal, but his energy and personality are back. It was very scary. I never had a dog that sick. I kinda lost it crying the second time I had to take him into the vet because he was so sick. I thought I was going to lose him.