Ketones would be one of the possibilities. Usually they are caused by an infection + no appetite + high levels/ too little insulin If that's a possibility, a vet visit would be a good idea, if you don't have ketone strips.
Other than that, I don't know. She doesn't seem to be too high or too low.
Can you wake her up? Can she move around? If not, I'd definitely get to the ER vet.