Ultrasounds?

I went to confirm my pregnancy and the doctor did a ultrasound from top and internally but could not see anything, not even a sac. Tests at home have been positive. They did blood work which will take 4-5 days to get back. I’m just thinking, is there no pregnancy at all or maybe it was too early to be seen on ultrasound? Last period/chemical miscarriage: 9/7/2024