An amazing amount of worries exists only in your head. Meditation helps see it, but even without meditation, if you simply think about it, your writing is a made-up world that at first exists only in your head, and only later, after you write it, starts existing on paper.
So most of your worries about your writing are just that, WORRIES.
Once you see it, writing becomes deceptively easy.
After all, you don’t know what will happen to it.
Will people read it?
Will people buy it?
Will people recommend it to their friends?
Will they like it? Hate it? Review it? Throw it into trash?
You don’t know the answer to any of these questions, so you see, worrying is pointless. Whether you worry or not, you won’t be able to predict what will happen. And worry will take away your precious writing energy.
So write. Finish your book. Ship it. Then see what happens.
Better yet, don’t even bother seeing what happens. Instead, start working on your next book. (That’s what Hugh Howey did, and look where he’s at now!)