Sleepwalking By Bring Me The Horizon.

I believe this song is about being stuck within the cycle of depression. At first he's so emotionally troubled, his body starts physically reacting to his stress.
The second verse is about what made him initially upset. He's remembering how things went wrong, and he's feeling guilty over the outcome. He also hates himself.

The third verse deals with emotionally numbness. Your psyche acts as if it's shutting down. It really does feel as if you're, 'sleepwalking' because being emotionally numb is like being stuck in a bad dream you can't awaken from, yet you're mentally conscious of everything around you. 

Fourth verse is the contemplation of suicide.

Fifth verse-he's analyzing his feelings and remembering why he started feeling bad in the first place.

Sixth verse-Still emotionally numb. He's also just, 'existing' by this point because he's already died on the inside.

Then the rest of the song deals with him wanting to find a reason to feel better. He's tired of feeling the way he does, but he can't snap out of his emotional turmoil. He wants, and needs help, but either doesn't know how to obtain or he simply can't seem to feel better because he's still stuck in the past over how things went wrong in his life.