You have mentioned that she is 14 years and she is having
thyroid problem. Since she is overweight, and is also irritable (suggestive of depression), it is likely that she is suffering from Hypothyroidism.
This appears to be the main cause. Hypothyroidism is known to cause depression, overweight, and also menstrual disturbances such as delayed cycles or excess bleeding (in some).
Next Steps
She may require treatment for Hypothyroidism with the aim of keeping her
TSH levels between 0.3 to 3 uIU. If her depression is clinically significant, she may also require treatment for depression. You need to consult a psychiatrist in person. He would be able to treat her and solve her problem.
Health Tips
The mention of a psychiatrist need not upset you. Endocrinological disorders such as
Thyroid dysfunction lead to psychological problems which need to be tackled from both medical as well as psychiatric angles. She would do very well within a month. Additionally, she may also be suffering from severe deficiency of
Vitamin D and Iron deficiency anemia, both of which need to be addressed too.