Traumatized brains are well known to have intermittent issues with reading (as well as other kinds of processing, storing, & accessing information), you might recall we used to have basic grammar rules on site because of it (and we still break giant blobs of text into readable paragraphs)...
...but some medications cause that, too. If you’ve changed your medications recently, that may well be a side effect.
...as does low blood sugar & low oxygen.
I know you asked specifically about disassociation, but all 3 of those things create symptoms similar to disassociation. They simply have a chemical cause (medication, glucose deficient, oxygen deficient) rather than a psychological cause.
(If I’m remembering right, and you’re new to asthma? Hit your puffer a couple times, wait 5 minutes, and try again.)