I can definitely relate to dissociation, too, and plurality to a lesser extent.
Really, I don't think enough people realize how many mental health struggles aren't something you "have," but what you don't.
Hell, I'm pretty sure there's been studies finding that depressed people actually have expectations more closely matching reality than non-depressed people. It doesn't make them pessimistic, it makes them lack optimism.
And yet somehow no one really talks about the void that can leave in a person.