Oh my!! Sallyanne prayers are already on the way for your sweetie pie. I am hoping that the vet can find the cause for this very quickly and that it is something easily treatable. Being in pain can definitely be a reason to not eat. I am sure you have given him the best non-professional exam that you can (feeling joints, etc.) Does he seem to flinch? I'm glad he is using the litterbox. At least that is a good sign. Oh dear! I will be on pins and needles until you return. {{{{{HUGS to you little Graemer}}}}}