I just read the story where a teacher asks her students how much does a glass of water weigh? The answer being how long it is held. A few minutes no problem and hour it becomes heavy and a few days causes pain , strain and fatigue. Anxiety works exactly the same way.
This is what differentiates anxiety from a disorder , can you put the glass down , or in my case get distracted and forget your holding the glass then put it down by mistake and cant find or remember what you were doing? Works just as well.