Hello, With reference to your problem regarding brain tumors, the anger you have undergone various tests and examination by your doctor without any possible clues that you are having brain tumors. In spite of the assurances given by your doctor, you are still worried about yourself and the future. Still you are not confident about yourself. This is nothing but anxiety disorder. It is a natural response when you are under pressure or facing a stressful situation. In moderation, anxiety is not a bad thing, sometimes it helps to stay alert and spur to take action. But when it exceeds then it leads to anxiety disorders. It is different from person to person. Some get it without attack and some will have uncontrollable, intrusive thoughts and leads to stay in tension, worrying about anything and everything. Symptoms include feelings of apprehension, feeling tense and jumpy, anticipating the worst, irritability, and restlessness, watching for signs of danger, feeling of mind going blank. Common physical symptoms include sweating, stomach upset, pounding heart, frequent urination or diarrhea, shortness of breath, tremors and twitches, muscle tension, headache, fatigue and insomnia and even depression. Anxiety attacks usually peak within 10 minutes, but rarely lasts more than 30 minutes. During that time it is so severe, you feel as if you are about to die or totally lose control. There are six major types of anxiety disorders. Not every one who worries a lot has an anxiety disorder. In your case, it is better you see your GP who can examine and may require a psychiatric opinion for further management. In addition to this you can adopt some self help like writing down your worries, create an anxiety worry period. Accept uncertainty, practice relaxation techniques, adopt healthy eating habits, reduce alcohol and nicotine, exercise regularly and get enough sleep. Hope this helps. Thank you.