Thank you for your query,
Get her complete examination by a Pediatrician
to look for anemia
, vitamin deficiencies, or any other associated nutritional deficiencies which are the common causes of tiredness
Thyroid profile to be checked once to see for hypothyroidism
Give her balanced and nutritious diet which contains all components of food pyramid.
Engage her to play games and soprts as physical activity make her alert and active.
Hope I have answered your query.