Low Iron levels -- when to see a hematologist for possible iron infusion

I'm 6 1/2 years post-op RNY and I've felt fantasti****il 2 summers ago. Then I had zero energy. And then all of a sudden I started getting migraines. I had testing done for the migraines & they haven't determined why I get them. Anyhow, I've recently had bloodwork done and my iron level was low. Hemoglobin was 10.6 the first time so my family doctor has me taking iron supplements 325 mg iron sulfate. Then bloodwork was rechecked again 3 months later. Hemoglobin was 10.8 and Ferritin was 8. He tripled my iron supplements (which btw I'm taking 500mg Vitamin C supplements w/ each iron pill.) I've read on here that our bodies don't absorb the sulfate iron as well as it absorbs the heme or carbonyl. So my questions are:

1) Should I let my PCP know about the other iron supplements & suggest that he prescribe one of those to me?

2) Should I go to a hematologist?

3) At what point does someone need an iron infusion? Does anyone know how low the Ferritin level needs to be?

I too had very low Iron once before a year after my surgery. I lost a lot of blood after in an incident dealing with postpartum and I wasnt taking my supplements as needed. I couldn't catch back up with my Iron levels just taking OTC Iron supplements. So I went in for my yearly physical and my normal post op blood tests...I had to get an Iron infusion immediately. That was 5 years ago and I still battle anemia, but I just up my iron supplements when I feel the urge of pica. I do forget my supplements too so that plays a part in the low iron. I have second guessed my increase in Iron supplements a few times and went to my PCP to get blood tested. The increase Iron supplements have always worked.