Hi Mary
I've had a problem with Iron levels nearly all my adult life due to A) a blood clotting condition and B) I don't eat any green vegetable's at all .
But a few years ago things got really bad, 1st my iron levels were very low, so I was put on iron tablets, then on my next blood test it was discovered my ferritin levels were very low, this was explained to me that ferritin is your iron store, and when your iron get's low it takes from the back up stuff, but it takes a while for these to build back up. Then it was discovered that my vit B12 was low also, so I was put on tablets for that too, it took about 12 months to get all the levels back to where they should be, my GP said it's a bit like a domino effect, as one will pinch from another, and only when it's all been depleted will you get the symptoms, I now have regular test's (every 12 months) and when my iron dips he puts me on tablets for about 3 months, this seems to work for me, hope I've helped in some way xx