Guys are hard to read. I would say he has an interest in you since he invited you over, but maybe he's a little distant/acting strange because you seem too interested in him?? Guys definitely don't like it when girls seem too interested. Even the shy guys... if they like you, they won't let you pass by. But from what you've said, it doesn't seem like you're really throwing yourself at him, or being too forward, so I don't know? If it was me, though, I would back off. I wouldn't be the one to i/m him first, or talk to him first, because you've done that now, so it's his turn. (and it will probably make him more interested if it seems you are going on with your life and your life isn't revolved around him right now).