Ultrasound question

Angel Rogers • 24 years old • Wife [9.9.17] • 2 blighted ovums 8/17/18 & 12/7/18 •TTC our rainbow 🌈 I have PCOS and blood clotting disorder

According to my last menstrual period I should be 6 weeks 3 days. Went for my first ultrasound and We saw gestational sac and the yoke sac. But no baby yet. Doctor says it’s too early to see baby. I had a blighted ovum pregnancy in August so I’m terrified. Anyone else see a baby with sac measuring 5 week 3 days but lmp should be 6 week 3 days?