My wife keeps complaining

Is it just with me or is it normal? My wife keeps complaining about her problems. She says she used to happy before marriage and now she is not. She is a type of overthinker who thinks of small issues and make them big in her mind. Then she becomes sad and complains to me. For example, she was saying that she is having a headache. I told her to take medicine. Then she said, she doesn't want to as it will become habit to take medicine. I told her to have a sleep but she said she couldn't sleep. She repeated of headache 3 4 times. I don't know what to do. Sometimes, I become angry becuase she just wouldn't listen. But then, she becomes more upset and situation worsens. What can I do to lighten up the situation?