I have symptoms of extreme long term insomnia, dizziness while standing, extreme fatigue relieved only by lying down, and excruciating headaches. Also numbness and tingling of extremities. I have had a brain MRI and it shows about 50 or more areas of white matter build-up. Curiously, my symptoms disappear for 2 weeks every 3 months or so, then they return. I suspect M.S. but my HMO resists that idea. What should I do?