Hi have you checked her BP? What about her Hemoglobin? These two can give her headache .

Happens due to hormonal changes.. give enough water and juices.. ask her to relax.. small walks in the morning will make her feel fresh..

It is normal to feel little lazy, just tell her to drink lot of water as dehydration can cause headache, tell her to go our for walk take in the fresh air she will feel better.