I Don't Understand Them

Hi, I'm a 16 year old girl. I like a boy in my class who constantly jokes that he likes me. My best friend likes his best friend. The boy my best friend likes has an ex in our class. He had said that he no longer had feelings for his ex, so she decided to tell him she liked him. He also said he liked her, but a little and invited her out after school, but the boy I like went with them. My friend asked him if he liked me and he said yes. When my girlfriend came home, the boy she liked and wrote that she still had feelings for her ex, and that's why it's best to stay friends. The next day I decided to tell the boy I liked that I had feelings for him, but he reacted very surprised, and said he didn't feel the same way about me, and that he did not suspect that I liked him and regretted that he had deceived me. Whereupon he told the whole class about it. I don't understand why they do that. Please give me some advice. Sorry if there are spelling mistakes.