6 weeks but no baby, is this normal??

I recently found out I was pregnant with baby #5

(2 living and 2 miscarriages)

I got many positives on a home pregnancy test and had to go to the ER for some slight bleeding

They gave me a vaginal ultrasound and saw a gestational sac but couldn’t see a yolk sac or fetal pole when I was five weeks and some days (see pic below)

My HCG came back as 909 on the 17th

And then I went to the doctor yesterday (27th)

for another vaginal sonogram and they saw my sac and possibly another sac but no yolk sac or fetal pole again according to the doctors notes but they want me to come back October 3rd for a follow up sonogram.

My HCG was 1,200 that day

Is this normal to not see a embryo at 6 weeks?