We get it: you think you can't write a book. You never know: you might be right. After all, book writing isn't for the timid -- a standard novel length can be anywhere from 50K words to 150K words (and maybe even more if you're George R.R. Martin). That's a lot of typing. Then you have to figure in knowing the story elements, character sketches, pacing, setting up the climax, reaching a truly satisfying ending.
Writing a Novel Is a Form of Art That Takes Practice
But understand this: you have to start somewhere, and guess what: if there was ever any genre that would be so well suited for a short type of format, it would be horror! And for good reason....
We've told horror stories before. Heck, there are even silly little two-sentence stories meant to bewilder us. The fact is you don't necessarily have to have a Bachelor in English to know writing mechanics. You, therefore, can tell a story just fine. You just need to know the obvious points to maintain: your character, several other characters (or you may not even need "other" characters as Edgar Allan Poe can so eloquently weave), a conflict, and an ending.
Don't stress about grammar. Forget mechanics. Write from the heart, reaching into your deepest fears, and conjure a micro-story from Hell that would make the Devil urinate blood. The bonus to just letting loose is that, yes, the horror genre allows you to not be so meticulous with the details or the mechanics. Free write. Give birth to a monster, however ugly it may be, and let that monster rage and rampage through literature.
You Start Like That -- and Then Work Your Way Up
Stories don't simply 'happen'. They evolve. They grow. They expand. And you never know -- the short story that was only two pages long may end up being your next large-scale novel leading to your first-ever horror book series. For real.