I remember having this experience on ayahuasca, where I asked what things would be like if I had never existed. Abuelita (the spirit/voice in my head/voice of the drug) said, remember that cute girl Jane who wore a ponytail and fluffy striped jumpers, who used to come visit you when you were 16? I said yeah. Abuelita said, well there was no such girl, I just made her up. I said "oh." I guess the idea was, if I had never existed, I would just be a fantasy in someone else's trip.

I also have this odd memory, which I've wondered about for years. When I was in 3rd grade, I didn't have any friends at my school. I do remember having one friend in that time, who had a curly blonde mullet. I don't remember his name, but he was at my school for several months. Then, nothing. I don't remember anything about him leaving the school. I guess it was just a dream.

Have you read anything about the Mandela effect? Might be interesting for you.