Hello and thanks for trusting me to help you and Candy today. I am a licensed veterinarian with over 30 years of experience and would be happy work with you.
Diarrhea with blood in it can be due to various causes including intestinal parasites, viruses, inflammatory bowel disease or even immune mediated causes, but it should always be taken seriously and treated aggressively, especially if she is also vomiting, which can lead to significant dehydration quickly in a small dog. When they are vomiting, oral supplement of fluids or oral medications are not the treatment of choice as it tend to further irritate the GI tract and lead to continued vomiting. On top of that, if her gut is that inflammed that there is blood passing with the stools or own it's own, she really needs to be on antibiotics so that the bacteria in her gut doesn't make it's way into her bloodstream and make her septic.
I would strongly urge you to seek veterinary intervention today for her. After a thorough physical exam, she would be best treated by fluid supplementation and medications given by injection until her gut settles down. In the meantime, I would fast her to give her gut a rest, but you do not want to let her go too long without nutrients either. These can be given at the same time as the IV fluids.
I hope this is helpful. Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please reply so I can clarify for you.
My posted replies are for general education only and not meant as a diagnosis. Only after a thorough veterinary examination can a diagnosis for your pet be made and specific treatments be advised or medications be prescribed.