Clarify 'fumes' ....  are you smelling natural gas fumes, is it only at home?  Call your utility company asap if that is what you smell.

If other scents are intensified - such as perfumes, fabric softeners, air fresheners, etc.; look up Dr. Claudia Miller's TILT theory (toxicant induced loss of tolerance).  drclaudiamiller.com/about-tilt/

Is there water damage in your home or workplace, current or previous leaks, floods?  Exposure to mold and bacteria from water damage can cause hypersensitivty to odors. If you could have a water damage problem, ask for help at Yahoo Health Group groups.yahoo.com/group/sickbuildings/

I react to odors like you (dizzy, brain fog, head ache). I smelled 'gas' when others did not, including the gas service person - I pushed her to be more thorough in her investigation and she ultimately found 2 gas leaks.

If you think hypersensitivity is the problem, look for an occupational environmental medicine doctor who understands it (not all do).

Best of luck

I found this link, may or may not help, but is interesting:

http://www.reuters.com/article/2011/10/14/us-smells-migraines-idUSTRE79D4L120111014

Melissa.

i dont have gas in my house. i smell the fumes everywhere i go,walmart,grocery,at my drs office,i smell it all the time.