D3 is most crucial (I only ever took 1000 IU daily, and my levels are off the charts for D3 in my body which is awesome).

If you got a full panel of blood work done, I'd ask about the vitamin levels that were tested to see if you're lacking anywhere.

I took D3 alone for a long time, then I began to notice leg cramping. I first though it was the MS, but now I'm not so sure... I read that if you're taking Vitamin D, it's important to also take in Calcium and Magnesium. So I take all 3 now and my leg cramps/spasms/popping feeling has subsided greatly.

I'd say those 3, but each person's different in what they need, so best to check with the GP or neuro to be sure. B12 is another that's very helpful for many (and many are found to be deficient in).

Sorry to hear about your diagnosis. Take comfort in knowing that we're here to help you with your questions, or if you ever need support.