"Keep your face always toward the sunshine, and shadows will fall behind you."

This was written by Walt Whitman

Now what does it mean?

Meaning

Stop looking at the past, especially when it's tragic. Now don't get me confused, there's a difference between looking into the past and reflection

The past is long spread usually reflecting on the bad things or embarrassing moments that happened months maybe even years ago.

Reflection is for the day or week which is more present and reliable.

If you were to get a source for information, would you trust something made years ago or yesterday?