Oh, I know - those words are a whole lot easier to write than to live.
But God didn't say, "Do not fear when your problems are small." He didn't qualify His instructions; they are the same, no matter the size of the obstacle we're facing. Whether your difficulty is the size of a molehill, a mountain, or an exploding volcano, His directions are the same: Do. Not. Fear.
He didn't say it would be easy. Unfortunately, fear is usually my first response to a scary problem. My stomach tightens, my body shakes... I'm often literally worried sick. But I'm working on that, because I know that fear is a choice. Jesus wouldn't tell us not to do something if we didn't have a say in the matter.
So how do we make the faith choice and keep the terrifying thoughts away? Maybe it helps to remember the choice that He made... to live in our world with us... to "pitch his tent in our neighborhood" (Max Lucado), so to speak. It helps me to picture Jesus just next door... when in reality, He is even closer than that; He lives within our hearts.
Whatever issue you're dealing with then, He is facing the same... and He's not worried. He knows He can't be beat.
"These things I have spoken to you, that in Me you may have peace. In the world you will have tribulation; but be of good cheer, I have overcome the world."
(John 16:33 NKJV)