Good question, Melaphant, and welcome to PsychCentral.
I think stress increases my confusion and diminishes self-awareness. Because I'm less aware, I'm more vulnerable to my triggers--they overwhelm me before I see them coming.
Especially when I'm depressed, I find concentration and decision-making difficult. Add stress and I have great difficulty (& anxiety) focusing, prioritizing, choosing. I am sidetracted (often subconsciously) by the stress, and thinking becomes plodding, scary.
Roadie