6 week scan

Cheyanne • Baby #1 is due July 26th
Has anyone else had an U/S and the Dr. Could only see the sac? This app says I'm 6 weeks 2 days, but my dr said I am probably not as far along as we thought so she wants me to come back in 2 weeks for another scan. I am freaking out a bit. We've been TTC for almost a year now for baby #1, and we were so excited to get our BFP. Just worried now.