There is a high probability that your body does not make hepcidin and you are a carrier, or have, C282Y hemochromatosis.
For a basic explanation as to how you would have low ferritin but have or carry hereditary hemochromatosis, see this post on FB:
[URL unfurl="true"]https://www.********.com/groups/591473358577668/posts/792355721822763/[/URL]
If on the other hand you are 55 or older, it's not likely but you may have a different HFE genetic mutation. I've run into a few guys who ran the protocol, it didn't work, and came up positive for hereditary hemochromatosis.