HCG levels not doubling, estimated 5 weeks pregnant, ultrasound normal?

The ultrasound tech said I’m measuring at 5weeks+5. I didn’t check ovulation this month but thought I should be at 6 weeks. I have had very slow rising HCG and my fertility doctor thinks it a miscarriage. Ultrasound tech sees gestational and yolk sack. She sounded hopeful, but I’m really guarding my heart. I’m bleeding a little bit. Should I retain hope? It’s hard when a doctor isn’t reviewing results with me