Talk to Gynecologist on Ultrasound Issues Really Confused

Salam, today i got my wifes ultrasound done, however the doc was not able to see the fetus but the sack and heartbeat were present, she checked again using a vaginal device to confirm , as per the gyne my wife is 8 weeks pregnant however as per the radiologist she is 6 weeks 6 days, i am confused, CRL was 0.87 cm, need help please if all is well, i have already lost one child after birth he survived for 4 days but died due to sepsis, my wife was 7 months pregnant.