5 weeks any ultrasound techs??

Hi I have been having slow rising hcg I finally got an ultrasound and it shows a sac but was curious if there are any ultrasound techs that have experience or if the same thing happened to u . I’m 5 weeks today my hcg has been 6-11 65 6-13 172 6-15 340 6-18 507 the are increasing just not doubling so it worries me . I would love to here stories and have input and no my levels are 507 in this ultrasound not a thousand