No baby only sac

Sarah

Today i went in for my first ultrasound. I should be 6 weeks 3 days. I tracked ovulation with opk. I’m measuring a week behind and only saw a sac. Today they checked hcg and i am going back for follow up ultrasound next week. I’m devastated and scared that this is not going to be a viable pregnancy. This would be my first miscarriage. Has anyone had a similar situation that turned out positive?