Every body beat me to it. I have the same problem, but mine is my own fault. I ground concrete for so many years I damaged my olfactory nerves to the point something has to have a very strong smell for me to detect it.
This "Anosmia" happens regularly to some football players when they get hit hard enough to catch a concussion. Team trainer/doctor will come to the aid and will make you smell ammonia to get your senses back on track.