I don't know if this could be of any help to you, but my mother experienced the same thing following a bad case of bronchitis about 8 years ago. She still has not totally gotten back her sense of smell. She went to a specialist and found that she has nasal polyps, non-cancerous things that grow in the lining of the nasal passages. Could this be what you are suffering from? Hope this is helpful.

~*~ rubyslippers ~*~