I don't know how this happened but I had a neurogenic shock1 yesterday, followed by low blood pressure.
This isn't the first time I was close to dying. 
It also once happened around 2016 when I was 15 years old, but not the same problem, but something related to the lungs.
In both cases I almost fully recovered. My legs still hurt for some reason and I'm barely able to walk. 

Update #1 : I'm able to walk completely as of 2021-06-28.
Update #2 : According to the hospital's reports, I was (technically) dead the entire past Sunday.

* https://en.wikipedia.org/wiki/Neurogenic_shock