Veterinary questions? Ask a Vet for Answers ASAP
I am sorry to hear you are having problems with Hallie. I understand it can be worrying and this is a difficult situation for everyone at the moment. I think it is unlikely to be anything to do with your cat, as she has been there for around one year we would not expect this to cause a sudden change in appetite. Has she had any vomiting or diarrhoea? There are so many different causes of inappetance in dogs. It is good that she had some blood tests which all seemed normal. Unfortunately she does really need a vet examination to be able to diagnose what is going on with her. Probiotics can be used and you can also offer her some bland food such as chicken/scrambled eggs/white fish. This will hopefully tempt her to eat. Otherwise, it depends on the underlying cause as to what treatment she will need.
I would recommend mixing this with her biscuits (can mash these up together) to try and encourage her to eat more.