I was told by a life coach, who has really helped me, that worries about health and phobias were caused by the fear of death. As part of a bereavement course I have done, I had to plan my own funeral and tell those close to me what my wishes were. Sounds horrible, but we all found it a rather healing process to start facing our own mortality. A book I have found wonderful, when I feel anxious, is called 'Dying to Live' by Anita Moorjani. It is about her experience of near death, which I find reassuring and I feel enabled to enjoy life now despite dealing with health issues.