Not sure if you were taking the Vit D3 but for what I heard is the best. I use Carlson and i started taking 6000 iu 3 years ago. Now that my level is @optimal I take 2000 or 4000 somedays depending if i been around sick people. The Article below may help you a little bit with info about Vict D3.
I'm glad to hear that you're doing so much better.