For what it's worth Tmcgee, most of the hardcore psychonauts here know what you went through and can sympathize. I understand your terror and the reaction to it perfectly.
While I do think that you probably had an NDE, I don't think you would have died. Without any other substances involved (stimulants, SSRIs, anti psychotics or the like) it is likely you just would wish you were dying... and those breakthroughs can be at least partly outside of time in spaces that seem to last forever. Having a horror trip that seems to go on for ages and eons is no joke.
Dark entities can really ruin your day. Any serious psychonaut needs to prepare for and train up their ability to avoid such encounters and rid themselves of such demonic presences in their life. It is hard enough when you know how to protect yourself... I really can't imagine how people with no such ability handle it. I am guessing they just block it out and choose not to remember these things.
Anyway bro. I really hope this is not your last post. I think you should avail yourself of this community. We are here for you. And... I
seriously doubt you will find a better group of folks to help you process and integrate your experience. Even talking about this stuff to "normal" folk only makes them worry about your sanity.
Just know that we are here and we love you.
HF
"Curiouser and curiouser..." ~ Alice
"Do not believe in anything simply because you have heard it. Do not believe in anything simply because it is spoken and rumored by many. Do not believe in anything simply because it is found written in your religious books. Do not believe in anything merely on the authority of your teachers and elders. Do not believe in traditions because they have been handed down for many generations. But after observation and analysis, when you find that anything agrees with reason and is conducive to the good and benefit of one and all, then accept it and live up to it." ~ Buddha