Sit down for some time alone and write down the thoughts which arise in your mind. Write whatever comes and do not edit or manipulate. Write down exactly what thought comes in your mind. Generally there is a tendency to write less negatively than as the thoughts really are. You are the only one who is going to read it so write them exactly as they are. As you have a list of thoughts, review them and come up with a plan to fix them. Think of alternative ways of thinking and transform the negative thoughts into positive thoughts.