My daughter is 10 years old, in less than the 3rd percentile for both height and weight and is always hungry. She eats and fills full at meals and then shorlty after is she gettingmore food or taking anything out of the cupboard. She does not gain weight and is tiny. Is there a medical issue I should be looking into? I have hypothyroidism. Could this be the way it is showing up in her? Isn't she too young for that?