I don't know whether this is menopause related, but for the last year or so I get the most annoying "rushes" that surge through my body right as I am about to fall asleep. It's feels almost like the adrenalin surge you get when someone jumps out and yells BOOO! from a dark room
(but without the fear/shock). I swear I can literally feel it coursing through my veins like a chemical.
This almost invariably happens during the daytime when I try to sneak a nap, and once it happens, I might as well forget it. My nap is shot. Luckily it never seems to happen at night, I'm usually able to fall asleep easily, and rest really well these days.
But I sure do miss those naps!