Looking back, I went thru some "weird" stages vaping. There were a few weeks about a month or so in, that I felt vaguely "not quite right."
It wasn't anything really strongly noticeable, just that I didn't feel quite like myself. Like I was on-edge all the time, fidgety, and this caused me to vape like I needed a pacifier or something.
this was a combination of quitting smoking, plus having to mess around a little with my ejuice nic level.
As it turns out, it was from vaping 18mg. Everyone told me as a new vaper that if I smoked a pack a day, I should start off with 24mg or 18mg.......WRONG for me.
I brought it down to 12mg, and I just started feeling calmer and less fidgety...immediately. Noticed I could put the PV down for long periods and do chores and errands with no problems.
Now I vape about 9-12 and feel great.