I Am Going On Vacation In 6 Days, The Day

I am going on vacation in 6 days, the day my menstrual cycle is due. My doctor gave me progesterone to try to induce menstruation early. 3 days of 2 pills and then 2 days of one pill. This seems to go against everything I know. I thought progesterone maintained preganacy/the endometrial lining. And it is actually the lack of progesterone that induces menstruation. Why would he prescribe it?