Have you got Long Covid? Brain fog and headaches are amongst the symptoms that can happen after this - which I know because I've been googling around to see why I was mis-typing things, flipping out of consciousness for a few seconds, etc.
I know I've got Long Covid - because I'm still deaf in one ear and still haven't got 95% of my sense of smell back.
It is worrying and I've mentally slapped my face very hard a few times recently - because I know I am very good at typing, for instance, to the extent that I could type away and at a very fast speed in a previous job and, at the same time, I'd be planning what I was having for dinner that night/what I was going to do that evening. So I've absolutely belted my mind one and given it one heck of a lecture for "misbehaving" recently and missing out words/misspelling words/etc. I think, in my case, either it was a pretty temporary blip (now gone) or my mind knows just how ruthless I will be with it if it keeps playing up and is scared stiff of what I might do if you see what I mean. I know I simply wouldn't tolerate my body being that big a nuisance to me personally....
Either way - that blipping seems to have stopped now and my mind is back under my control as usual.