Empty sac

I need some advice. I’ve been for a private early ultrasound today based on my last period I should be 6 weeks 4 but my periods are not always regular. There was a tiny sac but no yolk or baby. The tech I feel was really rushed and said it could be to early but if I’m concerned to go to the hospital. I’ve got an app at my hospital for later today but I’m so worried. I’ve cried all day I’ve already had 2 previous losses. Has anyone else had this happen and had a healthy pregnancy?