I am assuming your boy friend is young and has never had someone like you in his life before, he likes you more than his past girlfriends. he probably just thinks that is what he is suppose to do. Don't let his confusion confuse you. You should feel like you NEED him in your life before you take "i luv u" seriously, and that should take a lot of hanging out getting to know each other before that happens.
How old is he? I remember one guy telling me he loved me and we rarely hung out, and we weren't even dating. He was new to relationships, new to dating, etc. That's not to say he hadn't dated, just that he was still inexperienced. A month later he thought we should get married. Now, years later, he would never think of responding as quickly as he did when he was young and innocent. :)