Vitamin D3 is one of the few vitamins that will build up in your system if you have too much. Do not take it if you don’t need it. Have your blood tested before taking D3.
I got really, really sick on it.
That is unusual. But yes, you should test your blood levels of D3. Unbelievable that someone could get sick on it from the amounts in a commercial vitamin. I take a 10,000 IU cap every other day. This keeps my levels between 70-90. I take a multi K with it too.