Pregnant after MC advice

Ladies who got pregnant after MC, how off were your dates? I had only one period between the two pregnancies (which was almost a week late) & I'm measuring 2 weeks behind. So far 6 weeks with a shadow of what might be my yolk sac, when according to LMP I should be 8 weeks today. If it was blighted ovum, would a shadow be there? 🌈 thanks x