Since this is a thyroid disorders forum, we'll try to stick with thyroid function, mostly, but I may ask some questions that could relate to other issues, as well...
What was the reference range for the Free T3, Growth Hormone and Testosterone? Reference ranges vary from lab to lab and have to come from the patient's own lab report for the best comparison.
Was Free T3 the only thyroid related hormone that was tested? What about Free T4, which is the other main thyroid hormone or the pituitary hormone, TSH, which stimulates the thyroid to produce thyroid hormones? Both of those are, typically, tested with Free T3. If tested, please post their results and reference ranges. Were there thyroid antibodies tested? If so, which ones and what were the results, with reference ranges?
Has there been a thyroid ultrasound or CT scan? If so, please provide details of such.
Have there been vitamin/mineral tests performed for such things as Vitamin B-12, Vitamin D3, Ferritin/iron, magnesium, calcium, etc. If these were tested, please post results with reference ranges.
What about a Complete Blood Count (CBC) or Complete Metabolic Panel (CMP)? If tested, was everything within normal ranges?
The symptoms you describe could relate to many conditions, including thyroid conditions, vitamin/mineral deficiencies, other autoimmune conditions, growth issues, or anxiety of a 14 yr old.