6 weeks, 13mm only a sac...ANYone know/experience?

Heathirdd

So I went in for the first ultrasound today and DH came with me. The doctor estimated me at 6 weeks from the size of my gestational sac (it was 13mm)...but no heartbeat or fetal pole...just what looks like an empty sac, she said it "something" looked like it "could be" appearing on the lining, and my doctor said she wasnt worried and asked to see me back on Tuesday, about a week from today.

I know I shouldnt go google-crazy but I cant help but worry, things i'm reading say a yolk sac should be present by 13mm or it indicates a non-viable pregnancy. I know nothing can be set in stone but that is the most disheartening thing ever.

Has anyone experienced this??