7 weeks and questions

Had ultrasound today! Measuring 7 weeks! However the crown to rump is 6w4days. The heart rate was 118bpm. Tech said everything was good. Though the doctor said I had an either abnormal or enlarged yolk sac, can’t remember which one. She said though I’m vomiting and baby has a heartbeat things are looking good. However she did say that it could go either way, meaning miscarriage or viable. I’m so nervous as I just experienced a miscarriage in dec. any advice?