This dire feeling was inspired by the sight of the House of Usher itself. The excerpt is from the very first paragraph of the story, at which moment we have no idea who the Ushers are, what's wrong with their house (or them), or even who the narrator is. We just get to find out how it made him feel. It infused him with gloom, bleakness, and depression so great that he couldn't comprehend it or understand its cause. This feeling has two functions: it foreshadows that something bad is about to happen at this house, and it builds suspense by signaling to the reader that the house itself is haunted or cursed in some other way - almost as if it had a soul and will of its own.