Hi I Was On Birthday Control For A Week And

Hi I was on Birthday Control for a week and then I stopped taking them.I experienced Breakthrough Bleeding about 4 days later and it last me about 6 daystone themail same amount of time as my normal period. When should I expect my next period? Will it be the same time it would of been if I continuedon't taking the pill or will it be 28 days from the start of my Breakthrough Bleeding? If It was from my normal period I am 5 days late with a negative pregnancy test.