Bleeding 6 days before period

My husband and I haven't been trying but we haven't been preventing pregnancy. We are just waiting to see what happens. I am supposed to start my period in 6 days. The past few days I've had some bloating and some pinkish discharge. Last night when I wiped there was blood on the toilet paper and I had cramping lower back pain for a few hours. It was very light and nothing else after. But no bleeding today! I'm always very regular with my period. Could this be implantation bleeding? Thanks in advance!