Not only do I suspect that light effects me, but so does temperature. In the peak of summer I get sluggish, sickly, migrainy, swollen and extremely sick to my stomach...it exhausts me and I can't help but sleep. In the winter my bones hurts so badly and I feel constantly feverish, flu like and tired beyond comprehension. The pattern my husband and I have noticed is I become manic in spring and fall and depressed in winter and summer. I don't know if the depression makes the physical symptoms worse or if the physical symptoms make the depression worse....I suspect a bit of both are going on.