My cat has been acting strangely for a few days. After some (very expensive) tests the vet could find nothing wrong. He's an outdoor cat so I let him go in the garden and he is sitting in a bush near the house hardly moving and has been there since 9am. He is alive but hasn't eaten since this morning. What is he doing? He used to be super sociable and needy plus constantly begging for food and now is just refusing to interact. Has anyone has a cat do this? Were they ok?