I went in for my first U/S two weeks ago because of bad cramping. They dated me at only 5w1d when I thought I should have been at least 6 weeks. I was terrified and upset, thinking the worst. My hcg levels still looked okay from the week before the ultrasound, but I didn't really get much info other than come back in two weeks. So the positive part - went back today and saw my little blueberry with a heartbeat of 168!  Someone else posted a similar story and it made me feel a lot better while waiting, so I wanted to do the same for others!