Hi...hope you are well.
Take a look at this if you haven't already seen it. Hope it helps.
My internet connection blinked out, and I lost the post that I spent ten minutes composing. Basically, serum ferritin is associated with restless leg syndrome. Serum ferritin can be low, even when hemoglobin is adequate. This situation is not uncommon in women who are still menstruating, especially women who have heavy periods. Post again, if you would like more detail.
Oh, I just looked at your profile, and now I see you are 58, so I guess heavy periods isn't the problem. But if you have symptoms of restless leg syndrome, and you have low serum ferritin, I bet there is a connection.