Possibility of twins?

Haley β€’ πŸ’™πŸ’™ Baby Boy Due Dec 16' πŸ’™πŸ’™

So I'm 9w tomorrow and everyone keeps bringing up twins. For years I've said I wanted twins, and I'm seeing tons of twins on here.

But now I'm afraid I could actually have twins!

I had an ultrasound at 6 weeks and only saw one gestational sac and baby.

But is there any chance there could be a second baby they just couldn't see yet?

Does that even happen or has it happened to anyone?

Or maybe everyone is just psyching me out lol

Help!