The speaker is overwhelmed by the loss of a close friend, and the poem only reveals this in its final line. Until then, grief is shown through a world falling apart: stars collide, light fades, sounds disappear, and even the ground decays. It's as if the speaker's inner collapse spills out onto the universe itself.
The feeling is despair mixed with guilt. The speaker says they can never "breathe again" and cannot stand, and they picture themselves drowning in tears and a "vast, black sea." The last stanza makes the guilt clear: they will never forgive themselves for "loosing" the friend. The poem doesn't say how the friend was lost, so we can only sense that the speaker blames themselves.
The mood is dark, heavy, and hopeless. Repeated "never" and images of darkness, drowning, and sinking leave no room for comfort. The rhymes keep the lines tight and steady, which makes the sorrow feel relentless.