Okay, I think I'm starting to understand...
I get that you want to be a storyteller, and that's good - I wrote my first completed novel when I was around 16. It was terrible and unpublishable, but it was a big step forward, and a few years later I was good enough to get the contract for Diablo: Demonsbane. Starting young is a good thing, and the more practice you can get, the better.
But, I think this approach you're taking here is not the right one for you. You have to start by telling your own stories, not somebody else's. And, what scares somebody like me (mid-40s, husband, father of young two children, etc.) will probably be something very different than what scares you. The things that keep me up at night have changed as I've grown older.
So, what I'm going to suggest is that you take a look at your own life. At what times in it were you scared? What about those moments scared you? Why did those moments scare you? Dissect and deconstruct those moments, and then you've got the start of an understanding of some of the mechanisms at play. Once you have that, you can start constructing new scenarios for your characters based on those mechanisms.
(So, let's say that you had an incident in your life where you accidentally locked yourself inside a closet, and it was a couple of hours before your parents found you. Perhaps what scared you was that you could hear them moving around, but they couldn't hear you, or they were making too much noise to hear you calling out for them...so no matter how much you yelled, they didn't come. Digging deeper, perhaps the "why" was that you are frightened by the possibility of abandonment. Now you can take this information and construct a new scenario that doesn't involve a closet in which your main character has to deal with abandonment in a similarly terrifying way.)
The end result will be that when you write, your story will be informed by truth - your truth. Your understanding of what is scary, and why it is scary. It will resonate, feel personal, and have a fidelity that won't be possible if you're just copying somebody else's scary memory that you don't really connect with in the first place.
I'm also going to recommend a book - I only recently picked up a copy, and as I've been reading it I've been kicking myself for not getting it years ago. It's already helping me raise my game. So, I think it will help you too - it will give you a good sense of how to put the story together once you've got the idea in place: