If you had a RnY surgery you are not able to absorb iron taken by mouth (most iron is absorbed in the duodenum
, which is bypassed in a Roux en Y surgery). Ferritin is still low, but the best test is to get your iron saturation. You also need your hemoglobin
You will probably need iron infusions regularly until you get to normal levels, and then just every once in a while. Also make sure you get your vitamin B12
shots, and other vitamin supplements.