2003 Mazda MAZDA6 fuel system problems

I hit a deer at 45 miles an hour then hit the hit totalling the car, the airbag did not come out, the seat belt did not lock causing me to be slammed into the steeling wheel, now I suffer great pain, can't move my neck, can't lay down bc of such bad headache I throw up, I sleep sitting up, something in the car like metal fragment hit me in the left eye, now I can barely see out of my left eye. And must continue medical treatment.

I purchased my 2003 mazda 6s in october 2003. Since I have owned the car I gets poor gas mileage on it (about 16-18 miles per gallon). I do plenty of city driving but I still feel that this is not adequate. Even when I drive on the highway the gas mileage averages poorly. There is also a smell coming from the exhaust when vehicle is in motion. The vehicle also rev's up higher before switching from lower gears to higher gears. I do not 'jack rabbit' start or stop the vehicle.