I am, unfortunately! It is certainly interesting trying to work out what causes certain things, like depression / mood changes as both conditions have a bit of an overlap. My formal autism diagnosis is actually just a recent thing (albeit, I've known for years, but [a] it was hard to get the confidence to talk about it, and [b] the NHS psychiatrist didn't believe me so I had to get my GP to make a referral), so, in many ways the MS is what was formalised first.

Yes it is indeed difficult to say what causes what. I also got diagnosed with MS first and then autism. Dealing with both of these things.... Well, with only one of those it is like you are tired twice as much as normal people, but with two diagnosis it is like 4 times as much. What I find difficult is that sometimes I can't do anything because of MS and sometimes because of autism. And if those things don't overlap, it means I can be 'out of order' for 2 or 3 weeks. It is so unpredictable.