DCat (F, 6yo) has suddenly gone off her food. She returned from a couple of weeks at the cattery this week and on day one she was fine, then suddenly seemed to lose her appetite. She seems okay, a low bit key perhaps, and initially I suspected a hairball, but none has been forthcoming. I'm not sure what to do. She is usually really greedy and bolts down whatever I put out for her, but this is now day three when she's turned her nose up at her usual food (Applaws wet food + biscuits at bedtime).
I know, from experience, that if I take her to the vet with something vague they just say 'I can't see anything obviously wrong' and bill me a vast amount of money, so in the absence of anything other than loss of appetite I'm a bit loathe to take her. But what now? Try different food?