So nervous


According to my app I am 6w3d today had my first US and the nurse said there was a sac but she didn’t see anything. My periods are always irregular and we did an at home insemination on 11/10 and 11/12. My last period was 10/27 or 10/29 ( so irregular) could I not be as far along or? My first positive test was on the 11/17 but very faint I’ve had blood work done since and my HCG levels went up. Should I worry?