Ultrasound question

I know that everyone gets sick of answering these questions but I need some peace of mind!
Soooo a little more than a week ago when I thought I was six weeks I had an u/s. The tech only saw a yolk sac and said it looked to her like I was four or five and change and settled on 5 weeks 4 days. My doctor ordered another ultrasound.  I just got back from that appointment (theoretically now 6 weeks 6 days)?and still we just saw a yolk sac.   Is this pregnancy beyond hope?