Hi there, this is Dr. Elaine.
If this problem has continued beyond 48-72 hours in spite of offering a bland diet, she needs to be seen.
There could be something more serious going on which requires medication.
Despite her eating well, if losses continue via diarrhea, there will be severe electrolyte losses that need to be replaced, even more so considering her age. Please have her seen asap.
I am going off-line.
If she is holding down water and eating , then offer her plain Pedialyte to drink tonight until you can have her evaluated.