Long AF - last month now 7 days late Miscarriage?

Amanda
Last month I had 3 days spotting than 9 days heavy bleeding. Has anyone experienced that before? Now I'm going on a week late for AF. With BFNs. I'm confused. Someone told me today that I may have miscarried last month. If so could that explain why I'm late?  What are the symptoms of an early miscarriage?