Bloody diarrhea

My dog started having bloody vomit and diarrhea last Friday, 8 days ago at first vet said it was from stress because my family had just returned from a long vacation where our dogs were with a sitter. After 3 days when it just got worse she was hospitalized, given carafate to coat stomach ulcers, and steroids. After 2 days of treatment she started to improve but they still didn't know what was wrong with her. While in hospital her kidneys showed good function, she tested negative for any tickborne disease. 4 days ago she was seen my an internal specialist, but the vets treating her swapped out and a new one decided after an ultrasound of her organs to take her off the steroids. As of 4 days ago she came home and was showing signs of improvement, eating, wagging tail, seemed to have good energy. 3 days ago the bloody diarrhea returned in full and she has not been eating, (she also developed ulcers in her mouth causing her pain that we're treating with pain meds) it is possible that while we were away she ate something poisonous, but it's not likely. I'm hoping someone has seen something similar and can give us some input. -bloody vomiting diarrhea days 1-4 treated with carafate, steroids, Prilosec, and anti diarrheal showed signs of improvement while in hospital. -came home and after 36 hours of stopping steroids out of concerns it would suppress her immune system she started bleeding again -days 5-8 started bloody diarrhea again, developed large painful ulcers in her mouth, switched to liquid carafate which has slowed the blood but not stopped it, she refuses to eat, and giving her any meds including the liquid is a battle. We know she is negative for tick born, her red platelets we're/are low, giving doxycycline in case there is something the test didn't pick up      

Hello!  How much blood being lost here?  If fresh, red blood appears in a pets' vomit, it is likely that the pet is bleeding further up the GI tract than the stomach (blood in the stomach would often be partially ingested and therefore appear black) and if red blood is appearing in the poo, it seems likely that it originates in or beyond the large intestine.  If fresh blood is being seen at both ends, this implies that bleeding is happening at both ends of the gut and I wonder whether there are multiple causes of small amounts of bleeding or whether they are linked.   You don't mention clotting problems (have they been tested for?  Platelets are not the only aspect of clotting that could go wrong and can be prone to false readings if not counted by hand).  How about Parvovirus? Nor do you tell us where abouts these mouth ulcers are, the age of your pet or where your vet is up to with this case at present. Indeed, your vet is better placed to comment than we are.  Usually in complex medical situations, your vet would have a list of differentials (possibilities), may have disproved some of them and would be considering what test they need to do next to determine the cause.  At the same time - depending on the amount of bleeding - they may be taking such steps as trying to protect the ulcerated areas from deepening (eg some of the meds you mentioned), be monitoring the amount of blood loss in case blood or fluids are necessary, and so on. Questions you could ask them could include, where abouts is the bleeding coming from? Are the amounts of blood being lost manageable? What possible causes are there?  Are clotting disorders a possibility that need to be ruled out? How about parasites and infectious diseases?  What have they already ruled out, what do they think it is at present and what would the next stages be? How urgent is finding out?   We would be very interested in hearing how this case turns out.  Best of luck