Aly, when Filou was younger he was sometimes like that: not eating and hiding from us for a day or 2 and whenever he started eating and talking to us I knew he was getting better.

At that time the vet found his bloodwork was not ok but after he grew up he was fine.

Hearing that Chance eats and grooms himself is a good sign. I understand that it's worrying not to know exactly what he had but if he feels better this is the most important thing.