Should I be concerned?

Bella • Mumma to my angel Ayden and mummy to my little girl Mia 💙💓 love my little family but miss my little man everyday

Going off my last period which was the 6/01/18 I have worked out I should be 6weeks 1 day, last night I ended up at the hospital with some spotting and cramps, they sent me for an emergency ultrasound, they seen the yolk sac but no embryo, and then said that I’m only measuring between 4-5 weeks... I guess my question is has anyone had this problem and did use end up having a healthy bub? FTM