Help meeee plz sick with worry

Found out I was pregnant 9th April 2025 the day my period was due, my last period was the 11 of march meaning I should be 6 weeks today according to due date calculators online, I went for a scan today and a yolk sac was seen and they estimated me 5 weeks 2 days couldn’t see a heartbeat, I’ve had a tiny tiny bit of pink blood do you think the dates are just off or is there something wrong?