Petrified of having a blighted ovum

Laura • Married 30/8/14, little boy lochlan
I'm 4 weeks 3 days pregnant and I just can't stop thinking about seeing nothing but an empty sac on my 12 weeks scan :( my mother had one at 12 weeks, this is my first pregnancy and I really hope it goes well. I'm seeing so many people that have had one it worry a me its very common 😔