Hello, my Dad had surgery a month ago, and was fine until two days ago. Now he has uncontrollable shakes, chills, weakness, no appetite, and unsteadiness. Went to the hospital, suspicion of pulmonary embolism, but all seems normal. He recently started taking Zoloft 50mg qd, but hasn't complained about any side effects. He's 62 and in good health except for his injury at work ( he tore his biceps tendons on left arm, all went well, no infection. Please help, I don't know what to do.