I have fibro as well as developing Lupus that I'm being treated for. I also am low on iron. I've had tests and nothing found so have been taking iron pills and feel so much better. They think it is due to my very heavy periods (I have a fibroid) and am actually seeing a gynaecologist tomorrow to discuss options. Another item that can cause low iron is celiac disease. Have you ever been tested for that?
was diagnosed with fibro 12 years ago and yeah my iron levels drop too.I have ditched all medications as i have tried many and the pain still knaws away at me.the only thing i have had 100% success with is ultra muscleze powder it stopped the muscle spasms /cramps in their tracks!! found the chiropractor get rid of my pain almost intantly,but the problem is its the relief is temporary and its expensive.
you might need referral to haematologist. has dr prescribed/ instructed iron supplements? (sorry don't know about the link to fibro.) i'm getting iron drip this week. you could get drip, or a series of iron shots, intramuscularly. good luck.
and you being a fibro survivor for so long i hope you can help others on the board too!