Reply To: For the past few years, when spring begins to arrive, I generally don't feel well. Could this be due to my vitamin d levels dropping off after no sunshine for so long? I live in Southeast Alaska. I feel good in December when we are at the darkest part of our year. I take 5,000 to 10,000 iu of vitamin d a day, but I am gluten intolerant and think that I have absorption issues.