Advice about ultrasound findings

I had a ruptured ectopic pregnancy on January 28th resulting in the loss of my left tube. I did not get a period before getting pregnant again and testing positive on February 28th. I had an ultrasound on 3/11 that showed a 5mm gestational sac in my uterus. My ultrasound today 3/25 showed a 13.3mm sac (5 weeks 4 days) but no fetal pole or yolk sac. My doctor doesn’t feel comfortable deciding what to do yet and wants a repeat ultrasound next week (6 weeks 4 days). Has this happened to anyone and it resulted in a healthy pregnancy? I’m anxious and scared I’m going to lose this baby too.