About once every 6 months I remember to start taking my vit D supplements again. I've always taken more than the recommended dose because vitamin D is not extremely bioavailable in pill-form, and I notice amazing improvements in mood, mostly. Usually I am sad in the mornings. I have a cup of coffee, browse around on HN, and then convince myself to do work, and the sadness goes away with the distraction, and by the evening I feel pretty good for "doing so much work". When I take vitamin D, after about a week I begin to wake up and set to work immediately, leaving time in the evening for fucking around. I really should do that now, before finals.