Wedding stress: the pressure of wearing a white dress and traditions

Girls, next week my best friend is getting married and I'm going to get my period on that day, so I'm really cursing my luck. I have to wear a white dress, but I'm so scared that the pad might show or leak. Those who use tampons, please give me some advice because I've never tried them before and I'm worried about leaking, honestly I can't even sleep thinking about it. I really need your advice.