What Causes High Fever Along With Abdominal Pain And Dizziness In A Child?

I took my 8 yr old daughter to the emergency room last night with the following symptoms: High fever of 103° f, severe stomach pain (not localized) and very tender to the touch, nausea, upper back pain, stinging while urinating and dizziness. They did a throat culture, urine test and blood work. All came back clean. They gave her a saline infusion and sent us on our way with the diagnosis of viral pharyngitus. Today, her temperature has been as high as 104°f and after a dose of tylenol, down to 100.4°. She is complaining that the pain is unbearable and has vomited only once with a yellow, frothy consistency. She has only drank about 8 oz. of water and urinated very small amounts twice. Is this common for some one with viral pharyngitus or should I seek another professional opinion? Thank you for your time.