I was waiting for response from you.
In low thyroid status, there can be excessive sleeping, overeating, over weight, mood change etc..
Anxiety stress can produce such symptoms even in children.
As these are new symptoms, you should take her to doctor for initial assessment.
After physical examination, if the doctor feels necessary, he can take tests to know the precise cause.
I hope this information will be helpful.
If you have any query, please feel free to ask.
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Wish her healthy life.