Hi, if you're really desperate, try damage limitation:
how about a Dukan friendly hot chocolate to satisfy that specific craving? Theoretically you are allowed 1ts of fat-reduced coca powder as one tolerated item. Now that kind is hard to find so I have used 'normal' cocoa powder (like Green&Blacks or Bournville - NOT 'Drinking chocolate' or similar that has already got sugar etc added) and counted one Teaspoon as TWO tolerated so no other tolerateds allowed that day.
In a mug mix 1 TS cocoa powder, 1 or 2 TS dried skimmed milk. Add a bit of skimmed milk and mix to a paste before topping up with milk and mixing well. Heat in microwave for about 1m30s and sweeten to taste.
Better than giving in to a piece of chocolate or worse! Have a yoghurt sweetened and add a few drops of vanilla or some cinnamon, that's quite tasty too rather than the 'just sweet' taste. I also like to make sugar free jelly (Hartleys sachets) with half water and half yoghurt or fromage frais (make sure the water has already cooled down quite a lot or the yoghurt will split, which does not affect the taste but makes a funny layered effect when it settles ;-)...). Pour into four little ramekins/bowl and you're allowed to have three of those in any one day.
Stay strong - you can do it! If I can, anyone can!