[gavinray]

I take 20,000iu of Vitamin D a day (10,000iu morning/night).

You can take quite an amount of Vitamin D safely, an example: "Results of daily oral dosing with up to 60,000iu of vitamin D3 for 2 to 6 years in 3 adult males"

https://pubmed.ncbi.nlm.nih.gov/28012936/