The S&P and Dow had their worst two-day performance since Sept. 1, while indexes posted losses for the week. “It’s a confluence of all the factors: oil prices continuing to run down, the Chinese trying to counteract the dollar and everyone is digesting, globally, what the Fed’s announcement means for emerging markets and everything else,” said J.J. Feldman, portfolio manager at Miracle Mile Advisors in Los Angeles. The week was dominated by the Fed, which raised rates on Wednesday for the first time in nearly a decade.