I have been struggling for the past couple of years with the same symptons. I have gone to several doctor's and know one seems to be able to let me know what's wrong.
It usually happens when the seasons are about to change. I have dark circles under my eyes, i feel like my sugar drops and crave strachy foods. I am usually in bed for 2 weeks where i can't move my body because of fatigue. I have pressure in my head and very cold feet and hands. Just recently i have had some numbness in my fingers. I went to the doctor's and they had made go to have my blood checked. Nothing showed up after they took 12 bottles of blood.