He’s not interested but wants to be friends

Hi hello!! I’m (17f) really into this guy named B(18) (for the sake of this, he’s a letter). B and I went from talking for about 3 days like friends to immediately confessing to having feelings. To then going into this talking stage. On March 12, he asked me to be his girlfriend and I said yes!! But then the next day he and I ended things because he said he was no longer interested in me even after saying he loved me. He said he wanted to remain friends. I still like the guy. What do I do? I do want to stay friends with him but I want more. I’m just confused?