Yeah, I've known I've had a dissociative disorder for years, but it plays out in so many different ways, depending on my stress levels and my situation.
Sometimes I get in a textbook derealization space. Other times I switch alters. Other times I just space out, the lights are on but no one's home.
So there's still times for me, years later, where it's like, "What the hell is this!?" Dissociation is a spectrum thing - may have been mentioned to you already, idk. So just like a kaleidoscope of colours, it can play out in all different ways.
Typically it's an avoidance thing. And sometimes it's as subtle as your brain switching down a few gears because of emotions it's trying to avoid, or stressors it's trying to avoid.
You freaked yourself out a bit with something floating in the bath, right? That's sounded totally me. I see something that doesn't instantly make sense, so my head goes in all horrible directions instantaneously, and it can be sickening.
The stress from that alone, when you have ptsd on board? Could definitely set off a dissociative "Brain is overloaded and can't cope" state. Something that made you cry because it impacted you so much, even though it was brief.
Our stress cups run very full. Stuff like that can easily tip us over into 'not coping' territory, avoiding life and stress and emotions and thoughts (or any combination of those) by dissociating. When we do that? The psycho-speak is 'avoidance'. 'Avoidance' symptoms being in the medical meaning of the word Avoidance, rather than the everyday meaning you and I ascribe to it.