When I started this B12d journey it was noted my ferritin levels were the lower end of normal so I was put on ferrous fumarate for 3 months. Within a few days of finishing the supplements I had terrific headaches and vertigo. My GP said my ferritin levels could not have dropped that quickly and refused to test my levels (I was in tears in her office because I was feeling so bad). I could not put up with it anymore so I bought more ferrous fumarate and felt loads better within a couple of days. I then saw another GP that said he never had problems ordering ferritin level testing for a patient. He ordered the test and said my levels would be raised because I am on supplements but after 3 months he wanted me to take a months break then get tested again. The raised levels came back at 70 (which my podiatrist felt was not that high for saying I am taking 420mg ferrous fumarate. I have been on the tablets for just over a month but the insides of my eyelids are still white with very little visible blood supply (see photo), which suggests to me that the ferrous fumarate is not raising my levels sufficiently. Anyone experienced similar - do I persist for another 2 months and see if things improve? I am a bit worried that when I stop my levels will plummet and I will not be able to wait a month for blood tests to confirm my anaemia. I am si every other day with hydroxo and I believe this puts pressure on ferritin levels.