Fear affects you physically because of the stress that it places on your body. It causes eating disorders and insomnia, which is caused by a disruption of your sleep/wake cycle. You experience shortness of breath, chest pains, and hyperventilation, which causes reduced oxygen to the brain. Headaches and other ailments develop due to fear. These symptoms can develop into chronic illnesses and diseases, which eventually leads to death if not controlled immediately.
However, you should never let fear creep into your life. When it tries to raise its head, you better open your mouth and praise God. Also make sure you are prepared always by consistently staying in the Word, prayed up, and attending church each week. Surround yourself with faith-filled people and do not speak what is contrary to the Word of God.
These things listed above will not work if you have never accepted Jesus Christ as your Lord and savior. So today repeat this prayer and you will be saved and born again.