Lots of symptoms. Hello. Your daughter has symptoms that could be due to a serious issue, so she should have a neurological exam by her doc. She also should have her abdomen examined and possibly some stool or blood tests to determine the cause. If her pediatrician is unable evaluate her migraines/dizziness, she should see a neurologist. Increasing her water intake may reduce the severity of symptoms until then.
See a doctor. These symptoms should be evaluated by a doctor.