How far am I?? Empty sac

Daniells
My last period was on June 27. If i baby danced on 7/5, 7/7 and 7/22 and possibly ovulated on 7/11 or 7/12 how far am I? I had my first ultrasound on 8/13 and it showed an empty gestational sac. If I ovulated on 7/11 or 7/12 wouldn't I only of been in my 4th week of pregnancy when my ultrasound was performed? I won't hear from my dr until Monday or Tuesday and I hate not knowing what's going on. I think I ovulated on one of those days because i experienced spotting on both of those days. I thought my period was coming very early.
The tech said the sac measured at 5 weeks. She said according to my hcg levels being low it makes sense that I'm early...8/4 hcg was 101.5 and 8/6 they were 310.