I Wear Diapers

I have a question. I`m 16 and I just moved to Canada from England. I have a lot of terry nappies and plastic pants but sometimes its better if I wear disposable ones. In the UK my Mum got Tena XS pants but they dont have them here. She got me Depends Fitflex SM and they`re ok but they`re a bit big for me so they kind of slip down when theyre wet. Does anyone know if there are any here that would fit me better please.