Wall Street stumbled to a third straight loss on Thursday as U.S. stocks gave back more of their big gains for the year so far.The S&P 500 fell 0.5% and marked its longest losing streak in more than a month. The Dow Jones Industrial Average dropped 173 points, or 0.4%, and the Nasdaq composite sank 0.5%. All three indexes are still near their records set at the start of the week, though.Stocks felt pressure from reports showing the U.S. economy may be stronger than economists thought. While that’s encouragi ...