I had a really shitty experience three months ago. I had a relapse to some bad shit because I was around the wrong people and they kept handing me drugs. Through mixing them and taking so much at once, my heart stopped and my vitals dropped for about 1.5 minutes. I can't say for sure what death was like because it's all kind of a blur now, but I do remember hallucinations nonstop and then it was like that state between being asleep and dreaming (you know, the nothingness), and then back to hallucinations. I'm pretty sure that nothingness was death.
A year earlier, my cousin tried to commit suicide. Drank a bunch of vodka with a bottle of klonopin and also died for between 1.5 and 2 minutes, he reported basically the same thing. After his (dream-nothing-dream) experience, we jokingly concluded that there is no god. We were both atheists beforehand but that was kind of a turning point for him especially, where he lost remaining doubts. As for me, mine didn't reinforce anything, but rather confirmed what it feels like. I got to see for myself. I wasn't scared before, and I'm much less so after.
Through life and death, brushes with death, addiction, disease, all this unnecessary bullshit, I've concluded that the best approach to the topic of death is to just assume (right or wrong) that this is it, one chance, and give it all you've got. I might die tomorrow, but shit, if I could say I did the best I could, great.