Does The Scan Report Indicate Miscarriage?

Hi i am quite sure I am 11 - 12 weeks pregnant I went for a scan today and was told I have a slightly irregular gestation sac at 17 mm with a yolk sac but they where unable to identify a fetel pole, does this mean I am having a miscarrage. I had some very slight spotting 1 week ago which stopped. If this is a miscarrage why have i not started to bleed?