<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, I have been feeling dizzy and nauseous for a few days, and I also had an allergic reaction. Recently, I have been coughing and vomiting, what might be the problem?  <response>: It sounds like you might have a Vitamin B deficiency. Vitamin B is important for your nervous system, and a deficiency can cause dizziness, nausea, coughing and even allergic reactions. We can run some tests to confirm and then start a supplement to treat it. 