Beagle Is Not Eating, Sleeping Alot And Acts Depressed. She Is Normally Full Of Personality & Eats Anything. She Spent 3 Nights At The Vets With IV. Blood Test Came Back Fine. Had Diahrea And Vomiting But Stopped. Sudden Onset Symptoms?

My 5 year old beagle had a sudden change of health. Normally she is very active, very healthy appetite and has a great personality. She started with not eating, sleeping all the time and then not drinking. She had some diarrhea and vomiting. The vet kept her overnight on IV for 3 days. Her blood panel came back fine. She is drinking now but i can barely get her to eat 1/4 cup of anything. She acts very distant and depressed. Could the vet missed something? A stroke or some type of virus affecting the brain?