When Do Periods Begin After Stopping Duoiuton L?

hi,this is lavanya,i have been priscribes Duoiuton L for 21 days course of 3 months to regularize my cycles,i took them for 5 day of my cycle but i miss some days in between and completed the whole course of 21 tabletes,this is 3rd day after i stop the tablets,when i will get my period