I have smelled nasty scents in the grocery store, too...fecal matter, which obviously wasn't real but I sure could smell it. I just told myself it was just in my head as none of the other shoppers seemed to notice it.

I've also smelled cigarette smoke in the checkout line at the grocery store...like a cigarette is burning but nothing is there.

For me, the symptoms happen when I am very stressed out and if I am having trouble sleeping.

Take care.