Welcome, adventurer, to your destination.
You will find there is nothing here. Nothing for you to gain. Nothing to be contributed to. The goal you set never existed outside of your mind, and now that is has been reached it has vanished from being. Any feelings of accomplishment will soon make place for the nihilism that will drown out any sense of value you will ever manage to pull from your journey.
Learn to live with the wanderlust that cannot be sated, you will carry it forever. Try as you may to retain them, your memories will fade, but the disappointment will stay. Your scars will remain as scars. Not as mementos but as reminders of all the trouble in the world. Never lay your head to rest, for it will rot even faster that way.
Turn back, now, or tomorrow, or never. It does not matter. Wherever you came from, you will find nothing there, either.