Anxiety
Is an emotion characterised by feeling of tension, worried thoughts and physical changes like increased blood pressure, dizziness, sweating, rapid heart rate etc. people with anxiety disorders have recurring intrusive thoughts or concerns. They may avoid certain situations out of worry.
The mind tell the body to prepare for crisis and the body releases adrenaline causing the heart to beat faster, pumping oxygen through your body to increase energy and sweating to prevent overheating.
However when this reaction is frequently triggered in regular and not very challenging situations body can be left with headaches, fatigue and other stress symptoms.