Man! Watching that was strange.
I burned out about 7 years ago and it crushed me. I never had depression, as I interpret it, but I was in a bad way.
Stress from having a new family and being self employed took its toll and my body literally shut down on me. It got to the point that I would go to work every day thinking I was not going to make it back alive and that I would do the best I could to earn what I could to leave for my family. That lead to me not leaving my house for 6 weeks at all!! I was convinced , from the crushing chest pains ,that I was about to die any second. I could not even pick up a phone to tell a customer I was not going to complete a job because the pain would be paralysing.
I felt I was at the bottom of a very deep hole and the daylight was a pin prick. All I knew was that if I kept clawing at the earth I would be at ground level someday again.
I kept it all secret from my extended family and friends which was a mistake in hindsight .

One day I woke up and decide enough was enough and went to the doctors. He immediately said ' STOP NOW!'

It took me 18 months to get back to any kind of normality.

You are the first person who has interpreted that feeling I have ever heard.

Everyday was a struggle as my social anxiety was through the roof. Bit by bit I pushed myself and as you say it was fight or flight. My natural defence mechanism when backed into a corner is to lash out, and to some extent it still is .
The thing is I got to ground level and kept going and going and going.

Now I have invested so many days and years improving myself that I barely recognise my former self and even struggle to connect with 'normo's'.

All I see is people who have been through it and people who have not, plain and simple.

I see you use the term ' Forged in Fire' as well and it is the best way to describe it.

I do not consider my level of self improvement acceptable yet and I doubt I ever will.

Onwards and Upwards is my motto.

Good work and Thanks.