* TSX ends down 50.04 pts, or 0.4 pct, at 11,280.64 * TSX hits lowest level since Oct. 5 at 11,256.72 * Financial shares hurt by euro zone woes * Gold miners, energy shares rise with gold, gas prices * Disappointing Facebook debut hurts sentiment By Jon Cook TORONTO, May 18 (Reuters) - Canadian stocks hit a seven-month low on Friday, erasing early mining and energy gains as concerns about Europe's deepening debt woes and after Facebook's disappointing market debut fuel