As all we know, Poe lived in a century which was subject to change quickly. Unfortunately, he had to lament in every stage of his life. First of all he lost his mother and father. After that he lost his step mother and lastly his wife. So, it is easy to say that his losses of beloved ones affected the life of him so much.
Moreover, he was a very poor man. He earnt money by just writing critical essays, poems and short stories. Because of that he could not get in touch with the routine lifestyle of America at that time.
So his writings contain a huge amount of sorrow, mysticism and gothic images. Since, he was not a "happy", but a very sad man. He did not stop himself to include sorrow in his writings. That is the spell of him which affects us.