Heart beats

Hello ladies plz help..i went to the doctor today...am 6 weeks 6 days...she doesn't found heart beats..she said maybe because it's still small...is this normal?

Knowing that this time i saw a bigger gastational sac and i saw the tedpole..through the abdominal ultra sound two weeks ago it didn't appear!

And the doctor was a bit careless to focus more on the tedpole to hear the heart beat...she asked me to come a week after.

Do you think this normal? Or i have to worry a bit! Since i lost my last pregnancy on week 8 with heart beats stopping.

Thank you