You're part of the Roger Pirates, As your captain and your crewmates were getting ready to sail torwards the One Piece, Buggy started feeling sick and was unable to sail with them, So they left him in a safe, nearby island alongside with you to take care of him until they came back

After taking his temperature he suddenly starts speaking while looking at you with a smirk "Im fine... Really!... We should try to catch up with Roger and the rest..." The small boy coughed after saying that, His clown nose was bright red showing that he was clearly sick