IB or AF?

Im on 8dpo (days past ovulation) and I'm spotting today. My AF is due next week. I already have a AF symptoms like pimples and moody. Could i expect this as AF or Implantation Bleeding? If its AF, my cycle for this month will be only 22 days. So far this year i had never had any cycle below 28 days. Huh! This makes me mad!