Hi everyone

I'm feeling sick to my stomach with worry, I went for an ultrasound yesterday thinking I was 6.5 weeks and right away the tech said no way I was only 5 weeks (which is fine) dates might not correspond as i do not have regular periods but the ultrasound shows a very small sac with nothing else, has anyone had it look like this and all was good? I previously suffered a miscarriage before my son was born but I still have fears of it happening again.