When Can Menstruation Be Expected In The Next Month?

i started using novelon from the 1st day of my period on 21st may...but continued with break through bleeding. so i stopped today...ie after 13 days of having the pill. i am taking pause 500 to stop the spotting. could you please help me chalk out as to when could i expect mynext normal cycle...as i generally have my cycles reguraly once in 30 days