I really like this. There is a resonating depth to the last line-strikes you right at your center. I think you could make a longer poem out of this-these couple lines seem like a good ending to a poem themed around shutting the world out...try writing a beginning to it.

Overall, great work! Keep writing!

Short, yes. The meaning behind it? Endless.

Never try to add more to a poem just for the sake of quantity, it is a fools game.

I love this, it is straight to the point and all the more beautiful for it.

good work,

Alan.