The dog's lack of energy and red eyes may be caused by canine distemper or inflammation in the body. It is best to take the dog to the pet hospital for examination to confirm the cause and provide symptomatic treatment. If there are no other symptoms, it may be caused by internal heat, so you should pay more attention to the diet. Do not give your dog food that is heavy in salt. Try to eat something as light as possible. At the same time, you should also clean up the eye secretions of your dog to avoid bacterial infection in the eyes.