Sit back, relax, go talk to someone who actually does the job, and re-evaluate once you're better contextualized.
and, of course, writing HN comments.
employers can't screen for it because there's no paper trail.
It's especially unnecessary in a thread like this one where OP is doubting his skills and choices, and looking for help/direction.
In this context, it might actually help OP to relax a bit - the message is "Don't worry, you don't have to be a programming contest winner in order to work as a programmer. Many programming jobs are much lower stress and lower cognitive load than that", and abledon's description certainly matches my own programming job more than, e.g. what was described in the other "What was it like to be a software engineer at NeXT?" post on HN.
If it's The Social Network style code-bro'ing, coding the cure to cancer, etc; well that's pretty easy to find too.
There's a difference between a mechanical engineer, and a car technician. There's a difference between serious algorithmic work, and code-monkey work. One is more demanding than the other.