Empty sac at 8 weeks. What should I do?

Had my first scan few days ago. I told my gynae that I should be at 8 weeks eventhough my last period was around 10 weeks ago. He did a scan on me using the transvaginal ultrasound. But we found an empty sac. I broke down almost immediately, cause I already had one miscarriage last June. He said doesnt seems like the baby is developing properly and I probably had a miscarriage. He asked me to go back in two weeks time to check again. But I feel like I don't want to go in there and see bad news. Someone had this experience before? Could I be wrong with the date?