When you've had it, you've had it. You feel as if can't take one more step without losing your mind -- take a nap. It's that simple. Even a 20-minute power snooze will give you a fresh, new perspective. And try this: over the next few evenings, be in bed by 9 p.m. at the latest. Crawl under the covers with a good book and relax. A few nights in a row of solid sleep will work wonders for your constitution.