I see what you mean now...It's easy to get lost in the mind, especially for us who already have got the predisposition towards this.
I can relate somewhat, in my case it's more that feeling that in my stories I can make everything true or false, in the same time, and there is no limit, it comes from an emotional place, not from a logical place..Which is fine, because I love to use my words to express emotions, and that creates a surreal world where everything is possible. But then this fear appears that I'll start losing touch with reality in the outside world as well..
And it's scary because I feel like there is nothing stable and certain in this world anymore, there is no "handle" I can hold on to. There are those people who have their concrete, unshakable opinions about things. If I express am opinion, the second after I'm starting to think seriously why the opposite of what I've just said is true. And so on.

It just came to my mind that maybe there are different type of writing "states". There is the one where you are smewhat lost, trying to focus but getting more and more nauseus and cofused, but there is also the one where you let it go, no expectations, sort of "let the univers flow through you" kinda state.
I think it's not possibe to stick to one or the other all the time, but if they alternate, that's healthier I guess.
Writing can be healing and can be torture. Interestingly the result can be beautiful in both cases. I've been thinking if I need to stay in pain, just to be able to write...

I could write a lot about this topic...I think I'll stop here for now but if you want we can also talk outside this thread.