vitamin d3

Recently I have been evaluating and researching the many supplements I take on a daily basis due to insomnia and becoming fully awake at 3:00 am. Currently I am only taking vitamin D3 125 mcg twice daily and sleeping much better. Next week I am going to have elective surgery and read this...

I need to know how to convert D3 to D2 for dosing purposes, ie. D3 2400 IU and get the same dosage when using D2. I'm starting to have an allergic reaction to D3. If I lower my D3 dosage, I feel bad. Thanks.