I Took Ipill In Dec. I Had Periods After 8

i took ipill in dec. i had periods after 8 days n it continued until 15 days. then in month of feb, i had periods 10 days late than my normal period date. and this month march i had 7 days delay. but i am experiencing same flow as in month of jan. is this bcoz of ipill ? is there something i should worry abt ?