Bob's "Loud" is about how crowded a troubled mind can feel. Every line starts with the same word, and that repetition works like a drumbeat, or like noise that won't stop. The speaker moves from an ordinary frustration, trying to work in a noisy room, to something much heavier: thoughts that get louder when they hurt, and voices calling them names.
The last line is the most striking. Silence is usually the opposite of loud, but here it is loud too, and it comes with "a hole through your brain." That image suggests a numbness or emptiness that is just as overwhelming as shouting. Judging by the poem, the speaker feels stuck, unable to focus and unable to escape their own head, whether the noise comes from other people or from within. The mood is tense, tired, and a little raw. Writing in "you" rather than "I" may also pull the reader into that feeling, as if anyone could end up there.