I have a big question.

Crystal • baby#1Jayden7-24-15👼baby#2 6-1-16💙👶
Am I the only one who measuring a week behind , doctors thought i was 5 weeks 3 days but the blood result showed I was 4 weeks and 3 days . so nervous lost my first pregnancy at 38 weeks He was a stillbirth July 24 15 . plz help me .