I seem to need significant extra sleep if i take 5,000 ius of d3 before bed. i sometimes feel drowsy well into the early afternoon of the next day. should i take less? or is this indicative of a deficiency and i need to keep with it until my levels improv

Not clear: The relationship between vitamin D repletion, vitamin D deficiency, and sleep are not well elucidated and there is no evidence to suggest a relationship. However, if you have noticed changes in your sleep habits since taking the supplement, you should try to change the timing of the dose or the dose itself and you should certainly check levels to more accurately assess your vitamin D needs.

Wrong question: The way you sleep is not related to D3. Usual dose is 1000 or 2000u. You probably do not benefit from 5000. Was a blood level of Vit. D measured? Feeling drowsy is not related to D3. Once a person is found to have a low blood level of D3 it is not necessary to measure it again. Best practice is to merely continue daily D3 1000 or 2000u.