It gets better (if you have enough magnesium). lol. That was my problem anyway. And my high doses of vitamin D worsened my existing magnesium deficiency state! O_o After 6 months of 5000IU of vitamin D daily, sometimes up to 10 000IU daily) my levels only rose from 11.5ng/L up to 17.5ng/L. Not enough magnesium to absorb vitamin D.
I finally figured out what was wrong...a long time after that sad to say..doctors didn't have a clue (had over 50 symptom of severe magnesium deficiency!). Yay for the internet! :) Your symptoms are noted under a vitamin D deficiency including poor appetite. There are plenty more symptoms and a long list of health problems associated with a vitamin D deficiency eg: cold, flu, osteoporosis, higher risk of cancer specifically breast, colon, and prostate, higher risk of multiple sclerosis, increased risk of death from heart disease.... One vitamin you want in optimal levels! :)