Can’t see embryo !?

Ki

So according to my calendar I thought I was 8 weeks today. Had my first appointment tonight and they didn’t find an embryo , not the best feeling for first appointment of first pregnancy. So They think i might be more like 4 to 6weeks , new appointment next week to get ultrasound. I’m stressing it’s just an empty sac with no embryo. Anyone had this happen please tell me it’s just too early to tell . 😞