K.B.
Has she been able to eat and drink small amounts and keep it down? Does she still feel sick or does she feel ok? Any fever? Is tomorrow a full day of school or just a half day?
I would say if it's just a half day, she does okay the rest of today and tonight, and she feels fine in the morning, and no fever, I would send her. At this point, all you can do is play it by ear.