It is amazing to me too, geez, how quickly one of those dark clouds can just mushroom seemingly out of nothing. This happens with me as well. I'll be doing pretty well & then, for no real reason it seems, suddenly I realize I've become engulfed once again in one of those dark clouds.

However, as the saying goes, what goes around comes around. So here's hoping your black cloud goes on it's unmerry way, & your OK feelings come back around again.