Went in for a confirmation ultrasound

My doctor won’t schedule me or  consider me pregnant unless I have an ultrasound and blood test. I thought I was 5 weeks but turns out I’m 4 weeks and 2 days. She only saw something small and said I need to come back in two weeks since it was too early. They usually do the ultrasounds around 6-8 weeks. I’m nervous because she didn’t show me the screen so idk what it looked like....should I be worried. She didn’t sound worried but she had a poker face the entire time. My LMP was July 18th and I’m a 22-25 day cycle. Based off all the online calculators I used it said 5 weeks. Ultrasound showed differently. Anyone else experience this??