Iv been haunted by an experience that happened to me over thirtyfive years ago. I shared a house with a group of friends and we uses lsd as a tool or sacrament once a week. It seemed with each new trip new insights would come. Like a puzzle each new insight fit into place like a path. The funny thing is that it was very, like the insight meditation i'm now doing, one step leading to another.
However I had an experience on acid that shock the foundations of my being, i saw everything being caught in a never ending cycle of suffering that was inescapable, even death was no escape. I could see the beginning of the cycles and knew exactly how they would end. It was excruciatingly painful, when talking to someone, I knew exactly what they would say, as if i was in their head. Also if i meet other people who had had similar experiences we knew each other instantly. This mind state went on for some months, until i could no longer stand it and started to self medicate with heroin. This at least slowed the cycles down so that I could ignore them. After about a year as a junky and the death of friends to junk, i realized that we, my girl and i had to leave the city. So we moved to a very small town and, long story made short, raised a family worked,lived a normal life. But in the back of my head all the time was the fear that at any time I could experience that mind state again.
This winter I took a ten day Goeneka course and during the body scanning my body started to break apart into vibrations so much so that i stopped the meditation because i had the feeling that if i didnt i would explode. When I talked to the instructor he said it was just an experience and had no real significance. Shortly after the retreat while meditating and watching my breath being born and dying i started to experience once more the beginning signs of what I had experienced all those years before. Im fearfull that I'll have to relive that most terrible time of my life all over again if I continue to meditate.
What did I experience? Was it just drug induced psychosis? And how do I proceed from here in meditation?

You should know that when the mind is going through pain it can make up a narrative about what that pain means.

As for your experience of "endless cycles of suffering," I would bet that you were reading about spiritual stuff at the time, probably involving buddhism, the "cycle of suffering and rebirth," and other mystical mumbo-jumbo.

You came across mental territory that in this forum we call "dark night" or the "suffering stages." The story about cycles and death is just mental fabrication.

Insight practice is often about dealing with this kind of stuff. You will likely encounter this stuff in the course of your practice. It gets easier with practice.

If this is to hard to deal with, there are more gentle practices you can do, such as chi kung/tai chi.

Sounds like A&P experiences on drugs and then Dark Nights,
Daniel's book (Mastering the Core Teachings of the Buddha) has an in-depth cover of it, have a read
A&P (Bottom of the page)

Dark Night.

This happened thirty some years ago, before the internet, yep there was a prior time.

Thank you, i'll read the book, and see.