> I had no job, I ran on my savings, and the workplace I was interviewing for looked nice. OF COURSE I WAS NERVOUS.
100% this. I've never been nervous on the job, even during a work crisis. But I'm not a stage performer, and I'm super nervous during an audition, where strangers are standing over you, judging you, and you can lose the job if you do any little thing wrong, or even if you don't do anything wrong. That's so vastly different from a workplace situation. Yet a lot of people assume, wrongly, "If they're nervous during the interview, then they can't handle job stress."
Ask a firefighter, who runs into burning buildings for a living, to give a speech in front of a crowd of strangers. It's an entirely different kind of stress. Not all stress is the same. Fear of public speaking is very common, regardless of the person's job. The firefighter is trained for and experienced with one type of stress, but not the other. Firefighting is their job, not public speaking. Likewise, programming is my job, not interviewing. I can write code just fine, even if the whole company is metaphorically "on fire" at the moment, but my brain freezes in job interviews. And then an hour later, when the interview is over, I can often easily do the thing they wanted me to do during the interview, because I'm no longer in that specific fearful state.
The good news is that I'm now successfully self-employed, and my goal is to never interview for another job the rest of my life. Of course running your own business is stressful, and everything depends on me, but I've demonstrably been able to handle that stress. In a sense, the insane job market forced me to become an entrepreneur. (I'm also getting "older", which is another issue, i.e., age discrimination. It's commonly assumed that programmers get worse with age. Fortunately, my customers don't care how old I am.)