My "gut" is regularly way off.

I've lost count of the amount of times I've been driving to work thinking "oh shit I suck at my job I'm defo getting fired" to then be told " You're doing a good job keep it up"

Other time I think I'm doing a good job when everyone is actually very pissed off at me

This is my every day. "I suck and am worthless; I have no idea why I haven't been terminated yet." And this regularly builds to, "I've never achieved anything in life and, based on my past performance, likely never will. I probably should just kill myself now to save the trouble of doing it later."

I have two young kids though, so my wife thinks that's a bad idea.