Also remember if you take iron supps that they are absorbed best if taken with something like orange juice (or vitamin C/bioflavinoids), and that the absorption is inhibited by calcium and phytic acid, so try to take them between meals or well away from dairy products, grains and legumes. Same goes for zinc, magnesium etc.....
But haem iron (from red meat) is the easiest to absorb. If you don't eat it, then you really should consider an iron supp.
And it takes a while...3-6 months to bring flagging iron levels back up, so be patient and stick with it.