Good quotes are inspirational. Here's one that really speaks, "When the train goes through a tunnel and the world gets dark, do you jump off? Of course not! You sit still and trust the engineer to get you through." Corrie Ten Boom made that statement. It's so true too! Faith that overcomes the world demands focus. You will become what captures your thoughts.
When you feel sad or down, you need to shout and keep your joy on! When the heat is on, allow your thoughts to be captured by the Word and praise! One preacher said, "It's a poor dog that won't wag his own tail." YOU have to encourage yourself in God! 1 Samuel 30:6 says that at a very dark time in David's life, HE encouraged himself in the Lord!
If we really know God as our loving heavenly Father, we would consider fellowship with Him our greatest treasure. When the tunnel is dark stay on the train, trust the engineer and encourage yourself in Him! Being happy in the middle will determine how fast you get out of that tunnel.