AF Comes 6 DPO? What's WRONG With Me??

So, is it me, or is your body supposed to wait 2 weeks DPO for AF to start? Only 4 DPO, I had cramps, and by day 6, AF came! Could it be that tracking my bbt, CM, etc. has gotten me and my hormones all crazy, or could I be miscarrying this quickly? It's never happened before. Help me make sense of this please!