Yes, sundance when you step back out of full reality (so to speak) you are dissociating... derealization, depersonalization... all coping mechanisms. BTW we sticky posted Grounding Techniques at the top of this forum in PTSD. They are good for both anxiety attacks and flashbacks. I was sure you knew, sundance, the difference
Everyone dissociates...NO one is ever fully conscious of everything going on.. for that would involve, heart: beat, foot: take step, arm: swing... lungs: breathe... etc... so the processes we are fully aware of happening, we usually dissociate FROM... and focus on other events.

It's often that we dissociate FROM other events: when we drive... our mind goes to the song on the radio...and dissociate from where we are on the road, and miss our turn.
It's good that you were able to identify that you were triggered, and notice also how you felt different. (When I was first injured and flashbacking, I had NO memory of it. It took years and hard work in therapy to even get to where I now USUALLY know when I have been triggered and flashedback.) I'm working on avoiding some triggers.. and on managing others so I don't go on to a flashback.
IMO the "breath" is the most important grounding focus we can do. This works for both anxiety and triggers. When we begin to be fearful, we as human beings tend to hold our breath. This makes our body feel worse! It also prevents us from having capability to physically move out of the situation. If you can work on noticing your breath... and tell yourself breathe deeply.... hold it a few seconds and release it slowly... not only does it give your brain something to focus on rather than the trigger..but keeps you from hyperventilating. TC!!!! It's a skill you will use forever!!!