I do get overwhelmed easily...though I did astoundingly well on Black Friday. My shift started at 4:45am. I had to wake up at 3:00am. Our store was swamped the moment it opened and I was helping 5-7 customers at the same time. I got through perfectly well. Without getting upset, panicked or overwhelmed which really, really surprised me.
But I did have a moment where I spaced out later in the shift. I stopped walking and my brain shut down. I completely forgot what I was doing. But I'm pretty sure that was an absence seizure and not dissociation. During dissociation I'm still thinking. When the seizure happens, my mind goes completely blank and I can't think. Don't really move but blink.
Anyway....I'm to tired to know where I was going with this, but I found your words very encouraging.