Somalis usually get a minimum of 3-4 hours of sunlight back home. And since we diaspora obviously don't get the same amount of sunlight, we tend to have skin related issues (including hyperpigmentation). Vitamin D is not really a "vitamin" per say but a hormone that our melanin needs to synthesis and provide energy to different types of cells (fibrinogens, collagens, hepatocytes etc). And the more melanin you have, the more Vitamin D you'll need to function normally.
Having low levels of Vitamin D can also affect erythropoietin production in our bone marrow. Y'know how your car needs an oil change every 3000 miles? Your body does the same thing with erythropoietin as it is essential for creating new red blood cells every 120 days in your body. So any problems with new RBCs forming can cause iron deficiency anemia. That is why loads of Somali get this diagnosis.
If I were your doctor (which I'm not) I would prescribe you 10,000 IU of Vitamin D per day. Which is normally a high dose but you'll need it for your body to catch up. Iron would also be a good supplement for you but you should get a peripheral blood smear and a CBC (complete blood count) to confirm. Ask your doctor for a blood test and he'll know what I'm talking about. Goodluck sxb