I am sorry to hear that you have been to the emergency room so many times for this problem. I am glad to hear that your daughter is improving with the antibiotic treatment however, and she should definitely finish the course of antibiotics.
The fact that her white blood cell count, liver tests, and sed rate were all normal is also reasuring, as this means it is unlikely that there is a serious problem brewing that hasn't been diagnosed.
Strep throat is an infection cause by the strep bacteria. This is a very common infection, and it is easily treated with Keflex or other basic antibiotics.
Although most of the time strep throat symptoms include a bad sore throat
, it is well documented that, especially in children, sometimes the only symptom is stomach pains. Although this is not the most common presentation, it can occur. I am confident that, if the strep test was positive and if your daughter is now improving on antibiotics, that she will continue to do so.
I would definitely go ahead and keep the GI appointment, especially if she still has symptoms. Although this is likely just a case of strep throat, I think the GI appointment could provide some additional reassurance that she is in fact getting better.