It is a huge fucking mystery what happens after death. Many spiritual people, myself being one of them, are almost certain that there is an afterlife. We find this out through thought and psychedelics. But then again, there is that possibility that nature has set up psychedelics and made our brains capable of experiencing psychedelics to make our lives more interesting and prevent us from going insane. But then we ask the question, how can nature do such a thing? Does that mean that there is an intelligent mind behind nature?
Point is, there really is no point in troubling yourself over what happens after you die. Do what humans were designed to do: learn and experience. Nothing will better prepare you for the unknown.