Have they check your iron lately? If they did at the beginning, it could have been OK but now that you are making red cells, you may have depleted your iron stores.

When my husband's HGB was 5.5, his FE was at 392 which is high. That's because your body stores the iron from the missing red cells and the FE of 392 reflects the iron from the missing blood. This is true as long as your anemia is not from excess blood loss.