Has anyone ever been having a window and not realized?

Like has anyone realized that you might have been having a sort of a window and not realized it because you were suddenly slammed by a wave unexpectedly from out of nowhere? Like you thought you were still suffering but then an even bigger wave hits you.

I would say I had no windows until recent. Before then it was bad and then worse. My brother claims this happened to me but my memory of that time isn't too good. I think they call it a wave within a wave. It is also possible that things were slightly better but because everything feel crappy you can really see it. That could have also happened.

Ya everyone