I know exactly what you're talking about. I have issues with sensory overstimulation, and too much loud noise or bright light really saps my energy. Thought it might seem counterproductive, I listen to music to help clear my mind and calm my senses. Anything from classical to Rush really helps! I also download sound clips from Youtube and convert them to mp3s so I can listen to them on my iPod. My favorite is a 30 minute clip of a rainstorm. I can send you a link to the video on Youtube if you're interested.

Hope this helps