This makes me feel less claustrophobic

Literally and figuratively accurate.

Depends on your definition of "not there"

My blanket?

We are all mostly nothing

So when I am talking to friends, and going deep into a story, that means that when I ask them if they are there and paying attention, and they say yes, they are lying? D:

That's not true. It's about 48%, the empty space. They're mostly there.