Earlier quoted context omitted.
For a counterpoint to this - I decided to do 150 micrograms of LSD after reading a lot about it on HN, talking with many friends that had tried it or do it fairly regularly and reading as much as I could find (Sam Harris, Huxley, What the Dormouse said etc.). Nothing can really prepare you for it - the dream like state, the visuals and just the capacity of how different things can be. When looking at things I saw the…
I'm gonna bet you're not addicted to any external substance and that in your case, this was purely a mind expanding experience. One could also say LSD might have unlocked what was already there in the background (i.e. "subconscious") of your mind. I would not consider this a bad trip. More like a rude awakening. Had you gone through something else in real life, major trauma of sorts, you may have experienced exactly…
The challenging or scary part for me at least is when you rely on your own mind as a place where you can reason about things and then you start to worry if your ability to do that has been compromised.
The anxiety attacks after made me think that I really was dying or had a brain tumor or something and since I knew that the drug could no longer be in my system I got scared. I could no longer rationalize it as temporary affects of the drug. Researching all of the psychiatric information I could find online started to convince me that we know very little of how consciousness and mental illness actually work and I felt stupid for taking such a large risk.
Another thing I found scary is that a lot of healthy, normal people believe things I find absurd (like religion) and the information we're exposed to growing up seems to act as the training data for our neural net. I think consciousness emerged out of some evolved way to handle feedback and I didn't want to lose my ability to be able to reason about things.
The physical sensations after were really unpleasant (elevated heart rate, depersonalization, seeing visual patterns) and might have been caused by the anxiety that the LSD seemed to trigger. Also I had really low Vitamin D which seems to correlate with these kinds of issues too.
The fear of death I used to think about more than most people in a kind of distant way, but this experience made it feel imminent and traumatic - I think you're right that another life event could have caused similar symptoms.
I do worry less about things that aren't about people dying so maybe that's a good thing. It also comforts me a bit that everyone on earth is in the same boat, we're all sharing it for a limited time together and can work to make amazing things. Sometimes though, when I really think about the inevitability of dying it's still hard to go to sleep.
I think most people don't think about it.