Healthy weight but missing periods

5' 1" and 120 pounds is definitely not emaciated and I can't imagine you're carrying 20 extra pounds of muscle without looking like a body builder. There's probably something else going on and it's probably not tragic, but worth asking your doctor.

Have you ever had regular periods? When I was younger, I always skipped a month or two between periods and it wasn't due to being underweight or malnourished. Doctors just said it was taking a while for my body to settle into a rhythm. I think for me part of it was going on hormonal birth control very young and so my body didn't learn to regulate itself and any time I'd go off the hormonal birth control, my periods would be all over the place. Now that I'm almost at menopause, my periods are like clockwork. Go figure.

I can totally relate to this. I'm 5'6 and 148 pounds. My periods are very random. It's been 60 plus days since my last. Scale BF% says 22, but it changes depending on my water weight....so I'm thinking not accurate? I teach around 10 exercise classes a week...I will get period symptoms around my period and then no actual TOM. My dr would shrug it off when I'd mention it and bloodwork would come out perfect. Joining in to see your answers!

Do you always eat such little fat? Good fats are so important for hormonal health, cutting out too much will likely effect your periods a lot. Higher carbs will also help...maybe consider changing your % breakdown a little? You eat a lot of protein that may not be necessary...

I'm guessing you can't stop teaching the classes, but that amount of exercise probably doesn't help. I know that part is hard ...I'm kind of in a similar position, but train nearly 2 hours most days! It's a sacrifice I make to pursue my sport at the moment...