Implantation bleeding?

Brandy
I'm not due for my period for another 3 days (Friday).  I've had cramping and nausea sense Saturday. I started bleeding today. What is implantation bleeding supposed to look like? The blood is dark red no clumps and it's not heavy.  I've been wearing a pad for over an hour and there's nothing on the pad only when I wipe. Yes my husband and are are ttc.