Literature is writing, usually good, creative, or smart writing, or at least we hope it is. If you love books and have stacks of them at home, then you are a lover of literature.
Literature comes from the Latin root litterātūra, or lettered, but there are higher standards for literature than just something written down. Novels and stories are considered literature. If you're a practicing psychologist, you have keep up with the current literature on psychology, which is what researching psychologists write, not novels about shrinks. You might want your profession to be literature, but you'll probably have to teach literature while you're waiting for the book deal.