Losing sense of taste and smell

I discovered starting last Dec that some of my favorite foods weren't tasting as good as they use to and my husband would comment on a bad odor from garbage disposal and I couldn't smell it. My doctors say that with my chronic sinusitis and my asthma this is a common thing. So now I'm trying to learn what can I taste and appreciate now. Has anyone else had this problem? I'm told it can't be reversed. This could lead to safety issues in that I can't smell smoke, I may have a reaction to it, but not smell it.
The saving Grace is I can still taste chocolate.