7 days before AF...Pink and red spotting!?!?!

Received a positive OPK on 9/18. Now I'm on CD 25 out of a 31 day cycle and I am having red spotting, enough for a panty liner. It started off watery and pink. What's going on!?!? Implantation bleeding or an early start to AF? Am I officially out this month!?!? Please help...anyone!!!