Hi, did the doctor explain that ultrasounds after your first trimester are not accurate for assessing how far along you are? By the time you get to full term, they can be three weeks off. Usually the doctor will set the due date based on what the first ultrasound said. As I recall, in your first ultrasound, the embryo was too small to even be sure it was an embryo. That hasn't changed. Please see a therapist if you can't stop obsessing over unrealistic scenarios.