Ever have anyone ask you Is your book finished? Or What books have you written? Repeatedly? I once told a man who asked me what I was working on that I had a juvenile novel and several other short pieces. Every time I saw him, he'd ask Is the book published? I had to give a negative answer because I was still writing, still revising, still editing it. But I had been writing and publishing shorter works. He didn't care a twit about that. In his mind, if you're a writer, you write a book.
Of course, many writers do write books but a great many writers spend years writing and never write a book, not even a first draft. They concentrate on other kinds of writing including short stories, personal essays, critical essays, factual articles for magazines and newspapers, tv writing, screenwriting, poetry, short stories for kids, nonfiction for kids in the form of articles in children's magazines, technical writing, writing manuals for manufacturers and more. They are still writers and can be proud of their accomplishments. You do not have to write books to be a writer.
Don't ever feel less of a writer because you do not write 500 page novels. I'm willing to bet, however, that a good many writers of shorter works have an inner desire to write a book someday. That's fine. Maybe down the road, you'll do it. But if you never write that novel, only publish other kinds of writing, don't have one twinge of regret. If you are meant to write a novel, it will happen. If you need to let go and stay with your special kind of writing, be satisfied.
Many freelance writers make a steady income writing short pieces. They work just as hard as a novelist--maybe harder in some instances. They have to come up with new ideas on a constant basis. They often have short deadlines to meet. They deal with myriad editors, not just one.
We each choose the kind of writing that appeals to us and where we have had some success; perhaps it is the kind of writing in which we excel. I hope we can all reach a point where we can accept our writing and stop worrying about those people who keep asking if your book has been published yet. Face it--they have no clue what it takes to write a book and many of them never consider that all those short stories and articles are actually written by a human being.
Feel comfortable with your writing but remember that you can always look forward to trying something new at some time. Maybe you do have a book hiding deep inside you. All those short stories you wrote are practice for a longer project. And maybe someday, I will decide my novel has been edited enough that it is time to try marketing or epublishing it.