Psychic and Paranormal
Alright lets start with this site. First of all if you are going to ask a question try and keep it short as unfortunately some people are just not going to even read something that is as long as your post. I guess it just takes to much time for many people to get engaged with.
You can also use this site to look up questions that you may have. If you go the main page there should be links to blogs and comments about, let's say for instance, The Astral Plane, which you can click on and read what others have written about it. You can also Google the same and get definitions of things like, What is a medium?
And what I mean about past manifestations from a previous life would pertain to you having previous lives, Reincarnation, where some of the experiences that you had in previous lifetimes are showing up in this lifetime because they weren't resolved in that past lifetime. This also would mean that you would have to accept, or at least have an open mind to the possibility of Reincarnation.
I honestly don't believe that you are in any danger except from your own fear of the unknown. And you have to realize that there are many of us on this site, and none of us have even a fraction of the answers that are needed to explain all of this because it is a new universe or dimension all of its own.
In my belief, this new dimension is what humans are evolving towards as we spiritually awaken to this new reality which is why I say that you need to keep an open mind to all possibilities and read, read, read! The more you read about this kind of stuff the more understanding of it you will get, or perhaps, you will just decide that it isn't for you. But let me warn you right now, just because you ignore something, doesn't make it go away especially in this area of reality.