Fainiting and then having bad headaches.................

recently i have been fainting due to lack of poor eating and enemia also i have hypoglycemia. Well im taking iron tablets everyday and potassium tablets due to me having low iron and potassium. The er doctor saw me and the problem that im having know is that i keep getting there small little headaches that come and go and im wondering what is going on?
please help me.
Kelly marie Rogers