Canon doesn’t matter as much as your individual identity does. You don’t have to be completely canon-adherent for your experience to be legitimate.
Reality almost never plays out like fiction. It’s okay if your memories don’t play out as carbon-copies of a fictional work.
Canon divergence is a thing. The infinite possibilities of the multiverse means it likes to test out every little difference it can find from the weather to what shirt you wore, and more.
It’s fine to not find 100% matching canonmates. It’s okay to just be “close enough”.
It’s fine to be uncomfortable with doubles. Know that you are the only you, you’re the only one here with these exact experiences in this life and reality. If you believe in reincarnation, you are the only one here with your exact spiritual history. There are no true “doubles” or “copies”, just people who played similar roles in different universes.
Sometimes even two seemingly identical lives have small differences. What did you have for lunch that day? It’s the tiny differences that count.
Just because someone has the same memories doesn’t mean they were “the real you” nor does it really invalidate you. The universe usually doesn’t end when your time there does. Maybe any divergences started later on.
It’s better to be honest with yourself then to fit your identity to match someone else’s. In that same vein, no one can really tell you who you are but you.
Bad things done in a past life don’t mean that’s all you are. For one, nobody does bad things for no reason. You’re away from the cause of it now. Reflect on what happened if you can. Take the opportunity to learn from who you were then, just like you’d learn from your past experiences this life.