Hi BB... can I ask how tall you are and what your current weight is - and even how old you are (because you might be aiming low, and that'd take longer of course - have you been onto the official Dukan website to calculate your "true weight"? it takes into account the above factors, number of diets you've done, kids, etc. All these things which makes a low weight harder for us to stabilise.
If you eat sufficient protein, you won't feel giddy. We do eat carbs on Dukan, more than you'd think (I input my menus into My Fitness Pal, and come out at about 40g on a Pure Protein day and 60-65g on a Protein/Veg day). The oatbran we eat daily, which is carby... and some of the carby veg which are allowed once a day (every other day after Attack) too.
Once in Cruise phase, I'm full of energy. The Attack phase, getting into ketosis, can be more tiring...
Check out our menus to see what we're eating. All are in Cruise phase, but attack for 3 days should get you going nicely.