Hi-my 5 year old black lab is about the sweetest thing on earth, as labs are known to be. She has never met a stranger, thinks that everyone is her best friend, and is the best behaved dog I've ever had, especially since she has not had any formal training. She recently (in the last few months) began getting nervous in the apartment we live in--on three occasions, she has refused to go outside (not at all like her--she loves the outdoors), she puts her tail between her legs and acts like there's something scary outside the door. This has also happened one time while we were out and about downtown. She literally pulled me away from a certain area twice, something else she never does on a leash. Between these episodes, she seems fine, totally normal. I am worried that she might have some mental condition or illness coming on. Just wondering if anyone else has experienced this with their dog? She has always been perfectly healthy and "normal" till these nervous episodes. Thanks for any help!!