i'm amy and bandit is my 9 year old yorkie. he hasn't been doing very well lately. he's been walking around really stiff and slow with his back arched and seems to be trembling slightly. i am not sure if he is constipated (because this has happened before) or if he is starting to get arthritis. i took him for a drive this am and after that he had a big poop that he seemed to struggle with a little, but he is still acting the same. he is still eating and drinking fine but just wants to hide under the tables and be left alone. i have taken him to the vet about this and he had full blood work and everything was good there so i know he has no developing diseases. so any input would be greatly appreciated as the vets don't seem to be helping and are very expensive. thank you.