My 4 year old cat has been losing weight. She's always been healthy and a good weight. Lately, I've noticed her looking skinnier and when I pet her, I can feel her bones. I also noticed her coat seems to be a bit oiler and duller. She's eating, drinking, and going to the bathroom the same. I've noticed she's playing a little less with Henry lately but not much of a difference. Any advice of suggestions? Thanks!