Thanks for your query,
Your daughter is in her puberty
must have set in,so there are a lot of hormone changes in this age,
Anemia is also one of the reasons for tiredness
and dizzy spells,so a advise you to take your daughter to pediatrician
for general check up.
Give nutritious diet rich in green leafy vegetables.salads.fruit.
Avoid all kind of junk food and fried food.
Wishing your daughter good health,