Bleeding and Dr only sees gestational sac

I'm right around 6 weeks and started bleeding this morning. I had a miscarriage last July and we've been TTC for over 2 years. Finally we got pregnant again so of course I was really worried when I started bleeding this morning. 
Just got back from the doctor and they said that they only see gestational sac in uterus, no yolk or bean. He believes miscarriage is imminent. 
Please tell me he's wrong! Has anyone had the same experience. I can't lose this one! I'm just devastated and feel like I've been left with no hope...