Hi,
So I'm another one who used to have gorgeous thick, glossy hair, but over the past few years, it's really really thinned. I used to need to use special hair clips for thick hair, as nothing would contain it. Now, when I bunch it all together in a pony tail, it's the diameter of a 10p piece 
Because my hair is quite coarse, it can still look reasonably thick, but I would say it's half the thickness it was 10 years ago. The loss has really accelerated over the past few years.
Every time I run my fingers through, I get anywhere between 2 and 10 hairs. When I brush before washing, it's loads. Same as I dry it. Hairs are all over the carpet and it's a constant battle to de hair.
Thinking about it though, I've always lost a lot of hair, but it always stayed thick, so never worried about it. I'm obviously not getting enough/any re growth. Although I do have a few baby hairs at the top of my head, thinking about it. I hope it's re growth and not breakage anyway!
I'm also getting loads of grey and desperately want to dye it, but terrified of this increasing the loss. I have very dark brown hair, so it's a harsh contrast.
I do have quite low ferritin levels, due to heavy periods, so assume it's that, but can't seem to top it up enough. Started at 10, think it's now low 20's, but I heard it's needs to be 70 plus for regrowth...so a long way to go. I take as much ferrous fumarate as I can tolerate - 1 tablet ever 2-3 days and eat more red meat, spinach and have started taking floradix the past 2 or 3 months, but no improvement. If anything, the loss seems to have accelerated the past few weeks.
I'm having a thyroid test next week, but is there anything I can do in the meantime?
TIA