Is your dog having bloody diarrhea or it blood running from the rectum? Colitis can cause bloody diarrhea and vomiting; this can be very painful leading to her vocalization. Common causes of colitis include dietary indiscretion, intestinal parasites, viral infections, bacterial overgrowth, and stress.
Bleeding from the rectum, nose, mouth or other orifice is much more concerning and your dog needs to be seen immediately. Trauma can cause bleeding or diseases that lead to DIC (Disseminated Intravascular Coagulation)--these things need immediate care.
I would have your dog examined by a veterinarian. Chihuahuas are small dogs that become dehydrated vary easily. Your dog is also in pain. Your veterinarian can help find the cause and start appropriate treatment.
Bleeding from the rectum, nose, mouth or other orifice is much more concerning and your dog needs to be seen immediately. Trauma can cause bleeding or diseases that lead to DIC (Disseminated Intravascular Coagulation)--these things need immediate care.
I would have your dog examined by a veterinarian. Chihuahuas are small dogs that become dehydrated vary easily. Your dog is also in pain. Your veterinarian can help find the cause and start appropriate treatment.