Students require a lot of energy to work hard. Her sleep is a cause of weakness and stress. In my opinion she is in strain and tired. Tiredness can be due to insufficient intake of food as required by her body, or it can also be due to watching TV or working on compters.
You need to give her good health drinks eg, milk, juices and shakes.
Add food that is substantial in her diet like rice/dal, roti, puri with vegetables, protein and fiber rich curry.
If she likes taking eggs, give eggs and apples along with other fruits, antioxidants will help her gain health.
Add oats, cornflakes and try to keep changing her menu, add variety to food.
Avoid oily, spicy and junk food.
Restrict her from watching TV or working on computers for more than an hour.
Add a lot of vegetables in her diet, green leafy vegetables will increase the haemoglobin level and also minerals.
Set time to go to bed and help her wake up early in the morning. Make her do brisk walk and light exercises to boost up her energies.
If she does not show improvements yet, you can give her a health tonic eg, a B complex syrup or a multivitamin tablet after consulting a local doctor.
If you feel she is in depression try to see a local counselor at the earliest