Your brain is an incredibly powerful organ. Your thoughts can have a powerful impact on your mood and your life. Positive thinking often leads to smiles, success and happiness. Negative thinking can lead to anxiety, depression and at worst, suicide.
You need to treat your brain with the respect such a powerful organ deserves. If it makes you ill, you need to visit the doctor and get treatment. However, before it comes to that, take advantage of knowing its power. Use it to your advantage by saying NO to negative thoughts. What you are thinking is not necessarily true.
To start destroying negative thinking patterns, look at the articles on Predictions and Precautions, Finding Alternative Perspectives and Challenging Negative Thoughts, which uses the below image for support: