How do you find a sense of groundness in what you do?

For my profession, I think being anxiety ridden is a double edge sword. I'm not a perfectionist but I second and third guess myself enough for me to be careful enough to cover my ass. At the same time I'm never comfortable with my standing and I think the anxiety leads to burnout.

Ive seen colleagues who's in their 50s who feel even more uncertain then I am so I know it's not just me.

How do you find a sense of certainty?