question on weird smell

It's been a while and I am up about 20 pounds and it is so hard to get it back off.  But anyways it all relates to letting bad habits back in.  In any event I have had issues with low blood sugar in the past and no I haven't had my labs in a long while.  Lately though after smelling somthing burning in my oven which I took to being a dead roddent...don't ask....I now periodically smell this same sweet sicking smell at different times and places.  alot of times on my sofa and no nothing dead is in it....I checked.  Sometimes I smell it at work or in church....I don't know it starting to worry me.  Any clues?

Ketosis maybe?