Since you are probably exposed to the sun briefly now, working at night, and sleeping during a good portion of the day, you might have you vitamin D3 (the sunshine vitamin) levels checked. I'm guessing they are low by this point.
I thought this was a good article about testing D3 levels, and how to supplement when not able to obtain sunshine.
"Getting vitamin D right"
blog.trackyourplaque.com/2010/01/getting-v
itamin-d-right.html