Hi,
So in reality it's probably a few years on top of that, as I had been feeling crap for a while before I had blood tests, which came back to show I was anaemic and my ferritin levels were 7. I was told anything above 10 takes you out of the anaemic zone, so was put on ferrous fumarate and my levels went up to 14 quite quickly.
Job done, I thought. I carried on taking the tablets and my gp said I wasn't anaemic anymore, but because my anaemia was almost certainly brought on by my very heavy periods, it was something I'd need to carry on with, so I take a low dose to just keep myself topped up without the nasty side effects.
Anyway, my last results were 24, which I thought were good, but was then told by my new gp that they should be above 50, which was the first I had heard! After doing my own research, apparently that reading still makes me iron deficient, so no bloody wonder I still feel crap a lot of the time, as that's the highest I've been in almost a decade! Maybe more who knows?!
I'm genuinely quite cross that nobody has told me this before, as a lot of the symptoms, like low mood, trouble sleeping, palpitations, feeling faint, hair loss, I have.
Actually the hair loss is quite significant. I used to have really thick hair, but over the past 5 or so years, I'd say I've lost at least a third of it 
I don't want to take a higher dose of supplements, but I would have really ramped up the iron in my diet alongside and it could have saved me years of feeling awful.
Does anyone have any experience with this?