Hmmm, dogs will sometimes hold out for what would be called "the good stuff" like real chicken and steak but, coupled with lethargy and difficulty breathing a sudden disinterest in normally consumed foods is a Vet sign to me.
Are you running an air conditioner inside? Oh, wait, you are in Florida so maybe you think it's cold,
, so are you running the heat? LOL Either can really dry the air and forced air of either can put moulds and bits of stuff into the air which might bother her. That might account for the difference in breathing inside but ok outside.
But again, coupled with lethargy is a warning sign to Vet.