Dating scan way off - Bub too small?

Daina

Just had my first dating scan, I’m meant to be 9+4. Dr says baby measures 6wk and no heartbeat - but at 6wk she said sometimes heartbeat can’t be seen so have another one next week. Anybody been in the same boat and had healthy pregnancy from here? No bleeding, slight cramping, no other real symptoms just tired! Praying for a miracle but remaining realistic