Fetal pole, when should you see it?

I had an ultrasound at 5weeks 4days and they saw the gestational sac and yolk sac, but no fetal pole or heartbeat. The tech said she wasn't sure we'd see anything bc I was so early. My dr told me I was measuring right where I should be. I can't help but be scared, I go back this week, I'll be just over 7 weeks then. Does anyone know when you should see the fetal pole and heartbeat? I've been so nauseous, nothing like my first pregnancy. We lost a baby in May of last year and I can't help but be scared. At least we know it's not another ectopic, since everything was in my uterus. Any information would be greatly appreciated.