Help first internal ultrasound showed no baby sac or heart beat.....

I went to my 7 week sonogram today and the lady couldn't find no sign of pregnancy. My LMC was August 22nd. so I should be 7 weeks. But when the doctor did my transvaginal ultrasound, she said, I have had no bleeding, spotting or anything abnormal. Typical pregnancy symptoms. Not sure of my first HCG levels( I haven't gotten the test back) has this happened to anyone else? Please help!!!!! Thanks!

This was my test a few days ago at the clinic. I have an appointment with my OB-GYN on Wednesday.