Well, a helpful solution.. talk to her local vet and see what's wrong
with her. The same thing happened to my cat.. his teeth were starting to get rotten.. so we took him to the groomer's and cleaned his teeth. If that doesn't work, try putting bits of cheese, or bread in her food. But, if you've been changing her food, that will make her confused. Stick to one food for now, so she can get used to it. I hope she feels better soon!