I Am A 70 Year-old Female Who Began Experiencing Strange

I am a 70 year-old female who began experiencing strange smells about 20 years ago that were not valid. Ex.: I smelled brownies, very strongly, when none had been brought in or baked. The past five years or so, I have had smells repeatedly that are very weird, in that I can't describe them well. They aren't good. It is a bit of a mix of chemical, electric, and spoiled fruit combined. This seems to be the only one I have anymore, and it is getting really hard to take. It has awakened me at night, but I also smell them while awake. Could this be significant?