She has diarrhea for some days, and tonight she vomited blood and had blood in her stool. We went to the vet, and they gave her contrast fluid in order to x-ray her. She threw half of the contrast fluid up again, but they still could do it. they didn't find anything. They did ultrasound analysis, but they didn't find anything either. so they sent us home. My dog is getting worse, she is throwing up constantly (with blood) and is in a very bad condition.
What can it be? What can I do?