かという

それに。。そのとき僕は
外の世界で何が待ち受けているのかという不安だけでいっぱいだった。

What does ka to iu do in the sentence it is throwing me off, I remember this being somewhere in a grammar book I looked at before and I can't find it right now.

My attempt

"Whats more is... At that time (the thing) that was waiting for us in the outside world just filled my mind with worries"

EDIT:
Found it かというと ( you would think that~~)
does this structure require you to have the と at the end as well? Because all the examples in the book have
かというと, which makes me think the かという is something completely different.

Yep, と is required for the meaning "you would think that..."

Without it, i think it means "as an example", like "..かというものだ"

Thanks for reply,

Is my translation ok?

In this case it's just the indirect quotation of a question:
そのとき僕は「外の世界で何が待ち受けているのか」という不安だけでいっぱいだった。

ahh makes sense thanks.