Why Is My Child Vomiting And Having Abdominal Pain?

My daughter is 7. Began throwing up Wednesday last week. Took her to dr the following day Thursday since she also began diarrhea. They gave her a phenergon shot. She didn t throw up Friday but began again Saturday with vomiting and diarrhea. Sunday she was fine all day. Monday night complained of abdominal pain. Tuesday, today, she woke up throwing up and having diarrhea. Took her to er. Bloodwork and urinalysis looked good. Elevated wbc 18,000. No diagnosis. What do you advise?