If you're human, you will have those days when it feels like life is you against the world. Take courage in the fact that it will pass and you will get through it.
Whether you're going through a breakup or divorce, being newly uncoupled can seem inherently empty and isolating. Make the choice to embrace the solitude and cherish your own company. This will help you move on and forward with your life.
The prevelance of this truly human condition is why we encounter so many famous writers who write about loneliness.
When Verne's protagonist Cyrus Smith (sometimes translated to Cyrus Harding) is discussing a castaway who has seemingly lost his wits due to isolation he compassionately utters these words. His is a good reminder to us all that too much solitude may not be condusive to good health.
Unfortunately, Charlotte Bronte's heroine Jane Eyre had a rough childhood and goes through some hard, lonely times as an adult too. However, she remains strong clinging to the principal of taking care of herself even when she is lonely and despairing. This mantra is applicable for any of us who are feeling lonely, always respect and take care of yourself.
Fitzgerald's narrator Nick Carraway is often an outsider looking in on situations he cannot control, and all of us can probably relate to his sentiments. Sometimes all you can do is watch while things fall apart, but after that all you can do is try to pick up the pieces and fight through that feeling of loneliness.
While you may feel lonely, Joseph Conrad claims in this line that it is impossible for anyone else to understand our the way in which we uniquely experience life, just like it is impossible for them to experience our dreams. Inherently, we are all alone [just keep in mind, Conrad did have kind of a rough life].