I am the self-consumer of my woes;— They rise and vanish in oblivion's host, Like shadows in love's frenzied stifled throes:—(3-5)
Okay, okay, maybe the speaker is just being poetic. But maybe he's not. Maybe he really feels like he can see his woes "rise and vanish" right in front of him. This is a little crazy, don't you think?
And yet I am, and live—like vapours tost Into the nothingness of scorn and noise,— (6-7)
It is possible that "noise" is a description of how the speaker perceives the sounds around him. In other words, perhaps his mind sometimes hears people talking and interprets it as "noise."
Into the living sea of waking dreams, (8)
We can't imagine that a perfectly sane person would perceive life in this weird dreamy kind of way, so these lines offer a subtle clue as to the speaker's mental state.
Even the dearest, that I love the best Are strange—nay, rather stranger than the rest (11-12)
"Strange" and "stranger" could mean a few things here. Either the speaker's closest friends are acting different and thus seem strange, or they seem strange because the speaker's mind isn't all there. Which way do you see it?