did you share the acc with anyone?
did you tell anyone you were using osb and did they know your details?
what script were you using? official/unofficial?
did you fall for the "double xp weekend" scam?
did you give your account details to some other site?
did you check if you have a RAT on your device?
Many questions, but I promise you, OSBot does not steal your account details, and the details are stored locally if you were to save them to the client.