Help :(

I went in for my early elective ultrasound yesterday & according to my calculations, hubby and I did the deed on the 13th of April, I ovulated on the 19th & I tested positive at 9DPO which was on the 28th. Fast forward I should have been 6 weeks 3 days yesterday but the ultrasound only showed a sac measuring at 4 weeks 6 days & they believe they could see what they think to be a fetal pole but it was super tiny which they said was normal at that gestational age.. I got my blood drawn and it was 12,558 which is so very high according to google those levels should be around the 6 week mark which is what I was thinking I was? Hubby and I literally only did the deed once so I just find it odd that the calculations are not adding up. 🙁 I’m so very nervous. I have to go back tomorrow to see if my levels have doubled but the suspense is killing me. I would also like to add I have a heart shaped uterus (bicornuate uterus) so I don’t know if maybe the ultrasound didn’t pick up properly ? I asked for a transvaginal ultrasound and she said I had pretty good imaging abdominally & didn’t need to do the transvaginal. I don’t know. I’m so nervous. Has this happened to anyone ?