Interesting theory, that it was the caffeine not the lack of sleep itself. I had given up caffeine completely (I'm a real coffee lover and used to drink a lot of it, but then just couldn't tolerate it once the anxiety hit). Now I've noticed that one, not too strong, real coffee a day can really lift my mood and doesn't keep me awake as long as it's before lunchtime. So there may be something in that. As for some people being born worriers - I can't subscribe to that one, I was never a worrier before perimenopause and I wouldn't actually call myself one now, I'm not triggered by thoughts and I can control them - it's a physical process that causes my anxiety.
This is me to an absolute T