Premount N

Period Related problem

my period date was 5 th and i take premount n from 7th date per day 3 tablets for early periods. But its now 9th date my periods still not come and i am going beach holiday on 13 th. So should i take 1 tablet per day to avoid my period. Is it ok nor not pls suggest. I am very confused and i dont want my periods between 13 to 19th date.