I'm just about 6 months post concussion also. I've been working with a neurologist who checked all my blood hormone levels as well a some key nutrients (called it a neuroscience panel I think). He said that a head knock can impact hormones sometimes because the Pituitary got knocked around. Anyhow, most of my hormones were fine but I was borderline deficient in Vit D. Not too surprising considering I've spent most of the past 6 months laying in bed. Getting those levels up has helped me feel less fatigued (not all better, but a noticeable improvement) and more positive mentally. For where I was, he had me take 10,000 IU's/day for two weeks then 5000 IUs/day for maintenance. I still deal with pcs symptoms but this has helped...best wishes for your daughter.