I am going on a holiday with my byf in june and my period starts on the mid month which is the same week as my holiday . I am planing on taking the delay period pill called " norethisterone " couple of days before  the trip.Will the pill affect my period after that? , me and my byf are not getting married anytime soon ,we use glow to predict my fertily to prevent me from getting pregnant . Will the pill affect the the prediction and my cylce ???