My 6 year old black lab is sick. She has one eye that waters continuously. The light bothers it and she won't let me touch it. She also has blood in her mucus. She has so much mucus that she is constantly snorting it and licking it off her nose. She sleeps all day and doesn't excited about anything anymore. She is losing weight and doesn't eat much. This has been going on for a month and the vet doesn't know what it is. Any suggestions would be very helpful. Thanks.