Advancing a period is always set with failures, postponement is always better. Moreover, if you wish to prepone a period, treatment should be initiated as early as the first week of the cycle. At least a week of medication is necessary to create the hormonal
situation necessary to induce an early period. Since you have not done that, I would suggest going for postponement by continuing the medication, but, please remember, prolonging treatment for more than 20 days is not advisable as it has side effects. Hope this helps.