Prices would reach a high point at which traders would sell to reap their profits. That's apparently what happened Monday. Then as the market falls, traders buy new stocks at lower prices so they can make future profits, so the market comes back up. It's Wall Street's continuing dance, not a signal that the economy is in trouble. Inflation is stable.
Unemployment is down.
Interest rates are low. Daily situations will always vary, but the long-term prognosis of the stock market is positive. Even the national deficit is down, down to its lowest point since 1974. That's the result of months of economic growth and the resulting increase in revenue, and it's certainly good news. As we've seen this week, the business cycle remains unpredictable and isn't likely to shoot back up to such stratospheric heights anytime soon.