Did I just reject my ex crush and didn't even realize it at the time?

Well last year my crush at that time found out from others and then later on from me that I liked him. Well he had always stared at me from afar all the time but once he found that I liked him he all of a sudden wanted to be partners all the time and was always trying to talk to me again like he used to. Because I had rejected him once before when he asked if I liked which at that time I didn't. Then the next year when we come back from school he tells me he loves me all the time and pulls my hair and pokes me in the sides. And then one day he asks me a lot of dating questions and asks me who I liked and I told him I didn't like anyone. He kept asking over and over again and then eventually says," You're mean go away" with a hurt expression on his face. Then I told him I used to like him but not anymore. Now he doesn't flirt anymore and now has a new girlfriend. So what happened?