I find waiting for things physically exhausting. Waiting in lines, waiting sitting in a room, waiting on friends to decide what they want to eat, walking really slowly with an elderly relative: I find it all physically exhausting even though very little physical energy is required.
I’ve just finished “The Body Keeps the Score” which gave me some interesting insights into cPTSD. It did mention mindfluness but also covered a bunch of other options to approach treatment. Good luck and best wishes for your future health.