Vacays!!!

Hello everyone, I was actually wondering if anyone knows how to change my period date. My husband and I are planning on going to the beach next month and in my calender, the days in which I will be over at my vacations will be the days in which my next period is due. Also I kind of want to lose a bit of weight and I don't know how, anyone have any idea🤦🏻‍♀️🤦🏻‍♀️I'm desperate!!