My name is Catherine, I am 22 and I too have only taken one doctor prescribed Effexor pill last fiday, I am still suffering from side effects 5 days later (did not take more than one pill): recurring heartburn, increased anxiety, tingling shoulders and neck, sharp headaches. These side effects seem to diminish a little every day, now they only seem to occur at night. I really hope they go away permanantly very soon as they stress me out. I didn't eat or sleep for the first 4 days due to the heavy nausea and increased heart beat. I too was sure I was dying. Hope everything went well for you, I would like to have un update about your situation to know where I am heading!