Implantation bleeding???

So AF is due tomorrow, but today out of nowhere I went to wipe and boom!  Blood!  I always always always have cramps...bad cramps the day of and sometimes 2nd day.  And nothing.  And with the blood is a lot of sticky discharge.  My nipples usually hurt right before my period and then feel normal once I start, but they are still sore.  Looking for advice on what's happening...