Last year when I was doing my first Master Cleanse, I had a similar experience. After eight days of having nothing but the lemon drink I woke up about 2 am and could actually smell and taste Velveeta cheese. This might not seem so unusual except for the fact I don't really like Velveeta and hadn't eaten any in years. Still, the sensation was so strong it took all of my will power not to get up and drive nearly 30 miles to the nearest all night Supercenter and get some of that pseudo-cheese. I also had something like that happen when I was in town shopping and suddenly could smell and taste a Sonic Bacon-Cheeseburger, another food I have not indulged in for years.
When I was researching fasting I came across an article about "food spirits" that are stirred up while fasting. I didn't save this because the site was very new-age oriented and I don't really believe that Velveeta was ever alive and possessed a spirit. However, I have since wondered if perhaps the so-called "food spirits" are the chemical residue of heavy foods trapped in the mucus lining of the intestine, and as the intestine is slowly cleansed these chemical residues get in the bloodstream and let us experience that food again. This is just a theory on my part, but perhaps your experience is a sign you are cleansing at a deep level. At least one can hope so.