Help. No sac?

Ria

LMP was 7/10/2020 and baby was conceived 7/24/2020 on my ovulation day.. Something told me to get a 5 days sooner test and I was instantly positive with very dark lines. I went in for my first appt yesterday and he did the ultrasound with the wand that goes in. There was nothing, no sac no nothing. He took blood yesterday and tomorrow again to compare hormones levels. Is it too early to see anything? Was that the problem? Has this happened to you before and then later on you did see something? All he told me was that I had a 6 centimeter cyst on my left side but that it was normal and would go away