The dog suddenly stops eating, drinking, and has no energy. This means that the dog is sick. It may be caused by a cold, gastrointestinal discomfort, viral infection, kidney disease, etc. The dog needs to be observed for other abnormalities. If vomiting, diarrhea, blood in the stool, etc. occur, it is best to send it to the pet hospital for examination and treatment immediately. If it is a cold, you need to give your dog pet cold medicine. If you have gastrointestinal discomfort, you can feed some probiotics.