Miscarriage?

I just recently found out that I am about 6 weeks pregnant and have yet to begin my doctors visits. I have an appointment in about a week but three days ago I began experiencing bleeding, clotting and cramping. The cramps were pretty severe and the bleeding is about the flow of a period. I'm nervous for my baby and I called my doctor to try and get a sooner appointment. But could this be a miscarriage?