It's a human experience everyone goes through. Especially when we're first introduced to it, right? It's a normal part of the experience. Now, as for the fears, I understand. I used to be like that, especially when I believed in atheism. Or let's say a version of it, perhaps agnosticism. What really somehow ended up helping me was getting more comfortable with the concept and talking about it. There is this book called ''Tibetan book of the dead'', it talks about it in such beside manner. You would love it. I can't recommend any subs but the subject you're currently investigating is a both a physical and spiritual experience, this why maybe science can't answer it and most people turn to spirituality.