Miscarriage?

According to my last period I should have been 8 weeks along at my last doctor's appointment. I had an ultrasound which only showed I was 5 weeks 6 days with no heartbeat. They told me to come back in a week to confirm the viability of the baby (three more days to go). I have had no cramping or bleeding. I do however still feel stretching in my lower abdomen. I am 100 percent prepared to accept either outcome, but just wondering if anyone has went through anything similar?