TORONTO, May 17 (Reuters) - Toronto's main stock index rebounded on Thursday after hitting a 2012 low the previous session, as gains from gold miners offset soft U.S. jobless claims data and mounting worries about turmoil in Greece and Europe's fragile banking sector. The Toronto Stock Exchange's S&P/TSX composite index was up 49.80 points, or 0.4 percent, at 11,375.88, shortly after the open. It recovered after hitting a seven-month low on Wednesday at 11,298.46.