Hi helen41, unfortunatly there are alot of causes of high ferritin it can be raised by things like infection, but it is odd that you went from low levels and then it has kept on increasing with out taking more iron, have they ever done a test for trans ferrin saturation? it far more acurate then ferritin and iron for looking for conditions like hemochromatosis, thalasimia etc. If you have anymore information post it here and i'll see if i can help, To answer the other question is it associated with ME/CFS, no your not supposed to fail any basic tests to qualify for this diagnosis, so both low and high ferritin levels imply that there is probably something else going on.
All the best