What Causes Dizziness,light Headache And Numbness In Body?

I have been experiencing shakiness and light headedness for almost 10 years. This is a daily occurence. I have had various tests done including full blood work to discount anemia (I'm 22 and female).
Recently I have started to experience numbness in parts of my body, particularly when I lie down. Usually this is in my heels and inner thigh. I have read that diabetes could be a cause of this. Is it possible that the blood work done previously could fail to show that?