E.T.
Awesome recommendations below. I did blood builder while pregnant too, but my iron kept falling. My midwife recommended I take liquid chlorophyll daily and that seemed to keep me out of the seriously anemic range. I can't remember exactly why she thought chlorophyll was so important - but it has something to do with the hemoglobin in chlorophyll being almost the same as human blood hemoglobin (but with magnesium, not iron) and so it augmented my blood and allowed my body to absorb more iron. Something like that.
I don't know that the brand matters, but I took one from Sunshine Health. It takes like you're drinking grass, which is kind of awful. But if nothing else is working, maybe add this in too?