Issues with anemia

Patient: Hello, I have been told by multiple general physicians over the last two years (I move a lot) that I am anemic although very close to the lower limit of iron. I have been given oral iron supplements to take once daily. However I have stopped before the end of a month each time because when I start taking the pills my period comes early and when it does I see that the blood is thick and black, almost like a paste. I don’t know whether I should go to a lab to check my condition and what tests to request. would it simply be a blood cell count and hematocrit/heme analysis? Is the problem just a question of not getting the iron in the right way? It seems as if any supplement I ingest just ends up in vaginal discharge.

Symptoms: thick black period blood and early periods, craving red meat, dizzy/weak spells, pain in legs (quad muscles) without much physical activity.