The past couple of weeks i've been on prilosec but am still having stomach pains, headache, & feeling lightheaded. it's worse at night. gerd related?

Hard to say,: without a physical exam.GERD by itself wouldn't cause your headache and lightheadedness. Some people report headaches when taking prilosec, so that may be the cause. Your lightheadedness may be due to anemia or low blood pressure, or some other cause - which is why you should follow up with your Dr to determine why you are feeling lightheaded. Make sure you are drinking enough water to keep BP up