Good heavens, you must have been taking a lot of D3. Either that or individual D3 needs vary much more than I was aware. My D3 blood test last year while I was taking 1000IU of D3 once a day was only 51 nmol/L with a target range of 50-250 nmol/L. So I added a second 1000IU tablet with the second meal. I also added a K2/D3 supplement three times a week which contains 1000IU.

My D3 blood test a couple of months ago was 98 nmol/L (target range 50-250 nmol/L) which is better, so I will stick to what I am taking. What was your total daily D3 supplement intake, do you recall?

I'm aware that some crank "doctors" online push people to take very large amounts of D3, in the tens of thousands of IU a day, which can absolutely be toxic and harmful.
P.S. Depending on which country you are in, the blood test measurement units vary. I'm in Australia which uses nmol/L (nanomoles per litre) for vitamin D3. Other countries use ng/mL (nanograms per millilitre) which gives a much lower measurement number. IU (International Units) for D3 dosage are the same for everyone I believe.