Hello. I'm posting here on behalf of my almost 18 year old daughter. She started menstruating two days before her 12th birthday. She has pretty much only had a couple hard periods in her life, otherwise, a light bleeder. She started running cross country and track for her middle and then high school teams. September 2016, her sophomore year, she lost her period completely. She's only had one since which was "forced" by taking Provera. During all her running hard years, she still steadily gained weight. She went from 115 lbs to 134 ta 5'2". Her race performance was suffering. She's a perfectionist to a fault. Every single practice and race was stressing her out to the point her dad and I suggested maybe she should quit the team. She would text me during the school day with her fear of the hard workout or race that day. Finally, she decided to quit her last season of track to focus on her health and her "perfect" GPA/academics. Currently, she's been power walking with some abs and arm strength exercises.
We finally were able to see an endocrinologist who believes she may have PCOS. She had an ultrasound done, but there weren't any cysts, just follicles. All of her labs (LH, FSH, Progesterone, Testosterone, Ferritin, Cortisol, prolactin, DHEA-S, ACTH, Insulin, Glucose, etc.), have come back in the normal ranges. Her Estrogen/Estradiol was a bit on the low side however. We had her tested for hypothyroidism as well since she runs a very low body temperature, sluggish metabolism (hence the weight gain), hair falling out, etc. and that was normal. It's been so puzzling. The endo put her on Metformin this past January. She told her to eat a low carb diet cutting out sugar, bread, flour, junk food. (She's a carbaholic, much like I was so this wasn't what she wanted to hear.) Since starting a low carb diet the first week of January, she went from 134 to today at 125 lbs. Still no period, sadly. I will add that I am a thin pre-diabetic (runs in the family), and also eat a LCHF/Keto diet with her. We found with random blood draws, she has hypoglycemia - perhaps due to her previous high sugar / junk food consumption). Once after eating a turkey sandwich, we had her glucose tested and one hour after eating it, the lab showed her BG was 53! I will note that I had hypoglycemia as a young girl myself, and heard that can lead to diabetes later in life.
Sorry that I'm so wordy. I'm just so confused as to what is going on with her. From everything I've read online (which has a lot of contradictory info), we aren't sure what to do to get her periods restored. With the only lab low on her being estradiol, no cysts, normal testosterone, etc., could this really be PCOS? Is it perhaps in the early or mild stages at this time? Her endo said all you need are two symptoms to be diagnosed with PCOS - which she has.
1. Amenorrhea
2. Random dark hairs - a couple at a time on her upper lip, as well as on the side of her nipples (both breasts) that she shaves every day. That's it though, and very easily taken care of.
She is going to start another round of Provera once we get back from spring break vacation, as the endo doesn't want her going longer than 2 months without a cycle. Can't do more than that since she's not trying to conceive.
Thank you so much for reading my scattered thoughts. Any suggestions, natural remedies, etc., mutual experiences, tips, anything any of you could offer would be so appreciated. 
She's been on Metformin for two months now and has lost 9 lbs (also went very LC diet), but still no period. Not sure if it just takes more time, or if it's the correct treatment for her. 
Finished norethisterone today after been on it for 1 year 6 months straight!
