P.O.P. MINIPILL

I'm on my third month of the mini pill. I've had som irregular spotting and small periods. However, this month, I am 5 days late for my normal period. I always take my progestin only pill on time. Has anyone skipped a period on this pill (errin)? Has anyone had a late period or heavy spotting? What's your experience been like? I've been sick for the past two weeks and I know sickness and stress can delay a period..but I am five days late and it's starting to worry me. I have been 8 days late before though.