AT 6-7 weeks all the doctor saw was a gestational sack...?

Last week I went to my first obgyn appointment counting from my LMP I was 7 weeks but I used to be on a 28 day cycle. For some reason my last two periods move to a 35 day cycle so maybe I was 6 weeks. Either way I understand my doctor should have saw a yoke sac at the least. He got me very nervous using terms like it might be non viable. Anyway he said it might be just very early and he did a blood test to see what my hcg levels were to see if the levels indicated somthing should be there. My next prenatal appt is two hours. I really hope I get good news. Has anyone ever been in a similar situation and has turned out to be ok?