Hi
Thank goodness Stella is better. That must have been a worrying few days for you. I'm glad you took her to the vet so quickly.
In general when a cat that is normally a good eater goes off it's food then it is always a danger sign in my book and needs further investigation by the vet, asap. Better to have a full examination sooner rather than later as they can go downhill very rapidly especially if they are vomiting or have diarrhoea as well, but even in the absense of D&V, anorexia needs investigating.
I don't mean the odd time when they sniff at the food you have prepared but quite happily munch on a bit of chicken, but start to worry when they don't eat the chicken or other favourite food either or seem interested in the chicken but only eat a tiny bit of it.
(make sure before you panic that they are not filling themselves up with another source of food eg dog food or killed food, mice, rabbits etc. if they are outdoors
)
Elsa