What could this mean

Hi all, so I am currently 12dpo. My af was scheduled to arrive Christmas day, it still has not showed up, I took a test 2 days after missed period and it was negative, three days past missed af I noticed what seemed to be spotting for the beginning of my cycle, went to check later that night and it stopped, my cycles are very regularly usually 26 to 28 days. Could I still be pregnant or is af just really late