My period started on 12/22/10, I started pack of pills on sunday 12/26/10, which was the last day of my period. I took the pills for three days and then stopped. I had spotting 8 days later for a day or 2, Then I spotted again 11 days after that for a day or two. My period should have come on 1/21/11, but has not. Am I to calculate my menstrual cycle from the date of my last actual period or from the date that I last spotted?