I Started To Eat Novelon(21 Days Pack Birth Control Pill)

I started to eat novelon(21 days pack birth control pill) march 2015. I have used it last 25th july 2016. Then i'm not taking this pill and naturally my period have started 2nd august 2016 and it stays for 5 days. Again its start from 17 august for 3 days and the quantity of the blood of period was very low and colour was blackish. Again my period have started 28 august as same mode...please help me Sir...