10 month old Bull Terrier growling at me when at home alone with him and has snapped at me several times. He is usually a happy sociable dog - good with other dogs and people. But just doesn't seem to like me....is fine with DP etc. I work from home so am with him all day but I'm starting to not feel safe around him. He's medically fine but goes into s sulk when DP is out. Today I am trying to relax at home and watch a film while DP is out with friends and his behaviour is just strange - he's slinking around avoiding me and has growled at me while I walked past him with his fur standing on end and lunged at me. Not a happy situation and I don't know what I'm doing wrong.