Stress is a normal part of life. You may feel stressed after work, at school, or during an intense activity like running a marathon. Anxiety disorder on the other hand is an intense feeling that is difficult to control. It can be triggered by many different thoughts and sensations, including worry about your health or work obligations. Often people with anxiety disorders will not experience stress in the same way as someone without anxiety. People with anxiety disorders often need reassurance that they are doing well, which can cause them to feel more anxious.