Ultrasound

Victoria

I had an ultrasound last week when i thought I was 6w2d but it showed I was 5w6d. The fetal heart beat was 102 which the dr giving the US said was good, but then I got the report saying they want another US in a week as HB was low and they want to check viability. Have any of you had low bubba HB on an early ultrasound with no problems? Its making me anxious thinking that there may be an issue.