My g.i. referred me to a hematologist when I was having trouble tolerating oral iron. Over a period of several years, I saw 3 different ones and they all agreed that infusions were the way to go. They always monitored my ferretin and when it was low, they scheduled an infusion. They always gave me the boost I needed.
I have gone @ 1 1/2 years now without an infusion after having a second resection (and two units of blood)
I hope you feel better soon! Anemia is the pits!