Feelings
Love the fantastical diction!! Yet it's sad that it all comes to nothing.

.. that which is loved now, in the end, results into nothingness.

summary/paraphrase
The speaker is thinking first about the poetry he will not be able to access because of his mortality the success he may not get to have, then the love he cannot experience, and then that he might result to fame and nothingness.
interpretation
The two aspects of the world- feelings and thoughts- both, in the end, sink to nothing.

Both die without an eternal significance.

thematic elements/lenses
Action vs passive verbs. Expand some more perhaps.
literary features and their effects
theme of harvest ---> gathering of imagination and thoughts and such, a taking in of outside forces, whether those forces be on your brain or you writing them down. ethereal allusions---> vivid imagery of the glorious imagination which he is trying to access, making it more devastating that these things sink into nothingness. enjambment---> the busyness of his thoughts and life, But when he steps away form everything the pauses really affect the way his step back slows don and puts everything into perspective.
key lines
"--then on the shore/Of the wide world I stand alone, and think/ Till love and nothingness do sink." "When I have fears that I may cease to be/Before my pen has glean'd my teeming brain,"