I know it's normal for dogs to pant since that's their way of cooling down and sweating but my Yorkshire Terrier, Gizmo, keeps panting no matter what. He does it even when he's not hot or energetic, it's like constant panting. I'm also confused because he always sleeps with his tongue sticking out a little bit and if he's on the floor, sometimes he'll lick it. He drools when he's panting too and none of my other dogs do this, it's only him. My two other Yorkshire Terriers never done this before, not even my Chihuahua. Is something wrong with him?