Implantation bleeding or early period??

I am supposed to start my period 1/8 but Friday morning (1/1) I figured it had come a week early...Thursday morning (12/31) I had gotten this result on a test (see below). I am having cramping but the bleeding is pretty light- much lighter than usual for AF. I have used a couple tampons though, but not very much at all. It's more cramping and back pain. Thoughts? I'm about 11 DPO now.