I hear you are having problems sleeping. You must wait for sleep in peace. If you let your imagination run away with you when you are trying to sleep, you may never get to sleep. I will not think that you are growing spiritually until I see that you have become calm enough to sleep peacefully without restlessness.
Ask God for calmness and inner rest. I know what you are thinking- that controlling your imagination does not depend on yourself. Excuse me, please, but it depends very much on yourself! When you cut off all the restless and unprofitable thoughts that you can control, you will greatly reduce all those thoughts which are involuntary. God will guard your imagination if you do your part in not encouraging your wayward thoughts.
Live in peace. Your imagination is too active; it will eat you up! Your inward life will die of starvation. All that buzzing in your mind is like bees in a beehive. If you excite your thoughts, they will grow angry and sting you! How can you expect God to speak in His gentle and inward voice when you make so much noise? Be quiet and you will hear God speak. Live in the peace of Jesus.
Hmm. Someone was paying attention to my restless nights...