5 week 4 day scan showed no baby but only a sack:( ?

From my last period I should be 7 weeks 3, today i had an ultrasound and a vaginal ultrasound and my doctor only saw a sack. It was just a black circle that measured 5 weeks 4 days. I was really upset, I was by myself too. It was horrible was too worked up to hear what the doctor was saying ... they drew my blood, and im going back tomorrow to meet up with my ob gyn. I am scared of misscarrying. I still have pregnancy symptoms ( which just started this week). No spotting or bleeding or or even cramps. What is happening anybody have this happen to them before? Is it doomed to be a blighted ovum? My boyfriends sister already told everone I was having a baby. Can it be okay? I feel so empy. I've never been so sad.