Dumi Response: We are sorry to hear that the item did not work out for you. Because everyone carries weight differently, we do not recommend using body weight as a guide to finding the appropriate size. In the case of the 586 thong, the waist measurement is the most important measurement to use to find the best fit. In this case, it appears that a size Medium would have provided a better fit for your waist. DSM from Rowlett, TX