6 week gestation sac but no yolk sac

Hey there ladies,

Could really use some positive outcome stories! Went in for what I thought was my 8w first prenatal appointment according to lmp but during the ultrasound the doctor only found a gestational sac measuring around 6 weeks with no yolk sac or fetal pole. This is my first pregnancy and just freaking out. They have us coming in next Monday to confirm if this is a miscarriage or not. I have been feeling about the same for the last couple weeks: super tired, bloated, tender breasts with enlarged and dark areolas, little nausea but nothing too bad, and increases smell. Is it possible my little bean is just hiding or not visible yet?