Notify your doctor right away. It does sound like it might be an overdose. Usually, you have to taper off of risperdone (ie. don't suddenly stop it), but not sure if this is true if she has only been on it 2 days.
On a more personal note, after years on this forum, I do not like the use of Risperidone except in extreme cases. It has many side effects and there are other meds that can work as well. Do take a look at the many side effects of Risperidone.