It seems like a response to the stress
and hectic lifestyle. She should take a couple of days break from work; take adequate rest at home. Encourage her to consume more fluids. It is advisable to avoid coca cola. Instead, she can take more of fruit juices.
Since the CT scan
of the brain is normal, I do not think anything is seriously wrong with your daughter.
She must make some lifestyle changes like shifting over her work to day shift, moderate physical exercise daily and following a healthy diet.
If the episode recurs frequently, get an EEG of the brain done.
Hope this helps.
Wish your daughter a speedy recovery.