If it's darkest before dawn, than it is nearly daybreak at Carnival Corp. The company's stock price has been severely punished since the beginning of the year for seemingly phantom reasons. Last week it gave analysts solid grist to chew on as it sounded an earnings warning on March 17 after it said premium-priced Millennium sailings helped lift first-quarter profit and it was scuttling a deal to buy rival NCL with an Asian cruise company. Shares of Miami-based Carnival, which recently agreed to pay $600 million for the first trans-Atlantic liner built in decades, the Queen Mary 2, dropped more than 10 percent on March 17. Carnival, with nearly 8.1 million shares changing hands, was among the most heavily traded issues on the New York Stock Exchange.