A lament: A passionate expression of sorrow or grief.
Oh world! (such a sad place). Oh, life (how short and brutish). Oh, time (so short and then KAPUT you are snuffed out like a candle, you and all your friends, and your dog too).
On whose last steps I climb (we’re all walking the same steps, down or up, people and dogs and trilobites and camels and daffodils and amoebas and even the universe)
Trembling at that where I stood before (looking back at the past?)
When will return the glory of your prime… no more, o never more…
(this is a lament indeed. And he was so young to already feel this way!)
Out of day and night, a joy has taken flight (it’s depressing to think about)
Fresh spring, and summer, and winter hoar, move my faint heart with grief but delight no more, no never more (wow, nothing will make him feel good ever again. That’s certainly what depression feels like)
This is as good a description of depression as I've ever read. Shelley has really described the emotional toil and anguish that someone who is thinking about their demise and the demise of everyone and everything they love goes through. Wow. Makes me weep.