Hi welcome to the health care magic Your child seems to be having viral gastroenteritis as fever and stomach upset present She can be given pantoprazole like drug to reduce acidity and fast relief from gastritis Avoid giving her high spicy foods and excess fatty meals Give her more fruits and green leafy vegetables The stomach upset and nausea can be present as a feature of migraine also... For acute migraine attack ibuprofen usually tried and if not responding than higher group like rizatriptan given So consult pediatrician for examination and get prescription after that If your child symptoms worsen than USG needs to be done for further work up Take care