Do you think the churning may have been because your instinct was that it would end badly and you were fired-up for that (adrenalin etc) - but nothing happened? A bit like when you have a life threatening near miss and the feeling after avoiding it, all hyped up but no way to expend that tension?
Yeah, very revealing and for my part quite a surprise. Just reading about these things doesn't explain it all from the perspective of the autistic person, there's a lot more to it and I had a lot of difficulty getting my head around it to the degree I've even self-doubted my own condition to some degree. It's been a huge eye opener just how prejudiced my own views of autism were before I self diagnosed not even a couple years back, and even now I'm sure I still harbour stereotypes in my subconscious.
I find it's very draining, and it's hard to define how much is physical and how much mental, but it can leave me just wiped out sometimes. I think it also gets harder as I get older, I don't have the same energy reserves to just plough through regardless (which probably isn't the healthiest of things to do).