The thing about LP/ nat gas is that some people are "immune?" to the smell, and like you, if you get a sort of gradual thing going, you get "used" to the smell and may not realize you have a problem.
Bad deal, all the way around. When I was in "that business" I was lucky -- had a good nose for that smell.
THE IMPORTANT thing is if you smell gas and think it might be dangerous do ya know what to do?
Well, I'm gonna TELL you....................
Walk right out the door and leave the door OPEN. Don't disturb ANY electronics, switches, or electrical appliances. If it smells "clean" outdoors, and that is where the breaker box is and ONLY if it smells clean outdoors, consider yanking "the main."
Then get away from the house, and either use a neighbor's phone or your cell to call the gas company.
THIS CAN BE classified as an emergency. DO NOT BE bashful about calling 911, and don't let them give you any ess ech eye tee about it, either!!!! They can send fire, and or the gas company