Hi welcome to Health care magic forum. Your daughter has become lethergic, and dull means you should be catious, and immediately consult a pediatritian, for proper diagnosis and treatment.
She might be anaemic, infested with worms, or might be having some chronic infection like tuberculosis
. Of course don't worry, it is commen with most of the children.
I advise you to consult a pediatritian for confermation of the disease and treatment. You need to have xray, montouks test, besides other routine tests.
You can give her proteine supplements like complan etc for duilding general health. give her an egg daily, with all balanced diet.
Wishing a quick recovery of the child ,and thanks for calling.