What Causes Period Delaying Inspite Of Taking Penorit Tablet?

Hi doctor May i ask u about my period? My coming period is on 10th but i have to go on trip on 11th.. So i took penorit tablets to come early period.. I took 4 tabs twice a day Doctor.. From 2nd april to 4th april..9:00p.m to 9:00 a.m.. I m afraid that period didnt come!!i waited for 3 days...So i drunk a cup of ginger tea yesterday..because i want my early period..Do i still need to wait alittle bit days?i m surely thats not pregnency..plz answer my question..thanks P.S-i had took 2 penorit tabs for last month..at that time,i had waited for 4days..