Both symptoms you mention - headache and nausea - are present in many conditions and disorders. Before taking something to help you can try to find out what could be causing those symptoms.

You can try to consult your GP and some specialists if necessary. Beside a physical examination there are some standard diagnostic procedures can be also done: measuring the blood pressure, blood analyses (blood count, sedimentation, hemoglobin, liver status, kidney status…), urine analyses, sinuses’ examination, eyes’ examination etc.