Might try giving her peppermint tea. Peppermint helps ease the nausea and the tea will help keep her hydrated. Put honey in it if you have to. Honey has great properties anyway. She could drink it cold or hot, depending on her preference.
Abbie (6) has been drinking green tea and all types of tea since she was three. Tea has a lot of great properties. Different teas have different properties and amounts of caffeine, which is FAR less than coffee. White tea has the least amount of caffeine.