It takes awhile but you can adjust to a low carb diet, takes about 2 weeks for most people to make the transition. The body has to switch from metabolizing glucose to using ketones for fuel and it requires switching to making different enzymes. I would advise you look into a Paleo diet, it includes fruit, nuts, veggies and meats and eggs, I feel very good on it and it is naturally starch free.
For Vitamin D ideas you might want to peruse this web site: http://vitamindcouncil.com
There's one doctor on the Internet who says the only sort of D that works for his patients is oil-based Vit D3 (cholecaliferol) that the stuff in multis or calcium pills just doesn't work. He suggests that you take enough of it to get to at least 50 (of whatever the range is), it is at the top of the range and that is about 4000 - 6000 iu of the stuff if you're not in the sun much. He writes quite often about D3 at Heart Scan Blog
Hey, thanks for that link. I'll check it out.
I know what it's like to stop sugar/carbs. Holy cow.....if I do that again, I'll start slowly. Die off of candida can be WAY torturous! :-)