The roars celebrating the re-election of U.S. President Barack Obama on television give Mohammad Rehman Khan a searing headache, as years of grief and anger come rushing back.The 28-year-old Pakistani accuses the president of robbing him of his father, three brothers and a nephew, all killed in a U.S. drone aircraft attack a month after Obama first took office."The same person who attacked my home has gotten re-elected,” he told Reuters in the capital, Islamabad, where he fled after the attack on his village in South Waziristan, one of several ethnic Pashtun tribal areas on the Afghan border."Since yesterday, the pressure on my brain has increased. I remember all of the pain again.”In his re-election campaign, Obama gave no indication he would halt or alter the drone programme, which he embraced in his first term to kill al Qaeda and Taliban militants in Pakistan and Afghanistan without risking American lives.Drone strikes are highly unpopular among many Pakistanis, who consider them a violation of sovereignty that cause unacceptable civilian casualties.