Make peace with yourself
Learn to recognise and embrace the feelings of 'darkness' - take time to know yourself. Have courage and be patient with transient feelings of 'emptiness'.
Be STILL for a moment, don't panic, it will be ok.
Focus on one small task. Think of only this task and don't allow anything else to distract or overwhelm you. I find one small task completed well inspiring. Enjoy and reflect on the results of your small completed task.