Scan shown nothing

Found out I was pregnant on Sunday, due to my history I was able to be seen for a scan. They couldn’t confirm pregnancy and said it could just be very early however my uterus lining was thickened which they said is a good sign of early pregnancy. They also said I have ovulated from both ovaries. My bloods showed my HCG is 1200 so she’s confused as to why she can’t see anything in the ultrasound with a level like that, she said she isn’t too concerned about an ectopic just because I’m not in any pain or showing any symptoms. My periods are off sometimes by a few days so can’t pinpoint when I could have possibly ovulated to know how far along I could be. Each test I have done has been a strong positive and clear blue says 2-3 weeks. Wondered if anyone has been for a scan where you couldn’t see a single thing? She’s bringing me back in tomorrow for another scan where she will get someone to take a bit more time looking hoping we see something 🤞🏼