Lyric discussion by SethBabbitt 

Cover art for The Pantaloon lyrics by Twenty One Pilots

Ok, this is what I think it's about.

Pantaloon is basically another word for "Pants." In a metaphorical sense, Pants refer to responsibility and growing up, which I think is the overall theme for this song. The first lines refer to the loss of a loved one who had been suffering from mental illness, which would be an introduction to the real world, showing that nothing is perfect. As we all know, none of us should know this, it sucks. He learned way too soon that reality is coming and he needs to gain some responsibility.
The Second line is his father telling him that as he's getting older, he needs to start a family of his own and assume the role of the Man of the House, making him realize, "I've been raised only to do this." The Chorus refers to how bad things happen in life, such as tiredness, pain, and even trivial things like your favorite shirt being destroyed . Friends will lead you down a road of s**t that'll eventually drive you insane. The rap talks about living the life of a grown adult, and how he sees things and how things see him. He wants it to be over, because he wasn't ready for any of it yet. The last verse refers to how he wasn't ready for any of this, and he feels alone because he was thrown into something that he wasn't prepared for. He fears that he'll never live up to what everyone makes him believe he has to, and it's those fears that keep him going day to day.

This is just my interpretation of the song. Don't take it to heart that it's the solid truth, because I know just about as much as anyone else on the matter.

My Interpretation