I know 2 people who had low levels of vitamin D & felt horrible. I do have the fatigue where my bod just runs out of energy & I just can't keep going until I rest. In fact, I have most of what you described except weight gain, but don't know what joint pain would feel like. Since I take 500 mg calcium w/ D & try to get 30 min. of sunlight when there is sun, I doubt that would be it...unless my body isn't absorbing it. I've taken Celexa several years, but my doc decreased it by half when the research came out about what was considered safe for women to take. I set up an appt. for a well woman physical today. She always has a CBC drawn, but would that show up a vitamin D deficiency? I've had pain for over 2 yrs. & hate it when it's so severe I can't even sleep. Thanks for the encouragement & hugs.