Possible miscarriage

I am 8 weeks today according to the first day of my last period. Last ultrasound said I was 6 week 1 day (which was this past Tuesday) they still weren't able to find a yolk sac, baby or heartbeat) I went to the bathroom today and I am having bright red bleeding and have had two small clots come out. Am I having a miscarriage? I have mild cramps.