I searched for years to try to get a diagnosis after I hit my head after donating blood in 2005. I have been sensitive to scents/chemicals/etc for years but after that accident, I felt terrible all the time. i was researching online and found a blog/page by a woman who said after a head injury she felt tired, dizzy, and awful all the time. She noted a sensitivity to natural gas (when it is being burned for fuel-cooking/heating/etc). She moved to AZ where most homes are all electric, and felt much better. Well, we changed over our stove to electric and vented our natural gas water heater in the basement (bathroom fan in basement runs at all times), and I have felt better since. Also changed my diet. Was diagnosed with MCS and MVPS (Mitral Valve Prolapse Syndrome aka Disautonomia). I take several supplements and avoid certain foods. It has helped.