large sac?!

Cyleste

So i found out i was pregnant again currently 7w6d, i had a still birth jan of 2018, then a miscarriage april 2018, and i was looking at all the ultrasounds of all 3. & this pregnancy i have a larger sac then the others. Is that normal? (both photos are from my current pregnancy) the dr said everything is fine and the baby is right where it’s suppose to be, but i’ve seen a large sac can lead to a miscarriage?