Sounds like it could go either place, song. That's what triggers
do imo, they take us away and into a different time period (where the trigger is.)
Grounding is very important, if you can do it. Triggers result in dissociation... but what you are describing sounds like another part of you is coming forward and "doing" for you at those times?
That you realize you are being triggered is the first step in countering their effects. You can learn to know when you are likely to be triggered. Try writing down when it happens, and what you recall doing last, what music was playing or where you were or even, if you can, what you were talking or thinking about. Odds are, something in there triggered you.