I always get light headed on a diet. I have normal blood pressure when I'm overweight but as soon as it starts coming off, my blood pressure drops and I start getting light headed and even seeing stars. Doc told me to add salt to my food. Obviously that's not so easy on this diet but I do find an extra couple of litres of water helps - and coincidence or not but since I introduced daily exercise its got better.
Also, I'm not sure about having just two food packs and a low carb meal. Exante recommend three packs on TS to ensure you get all your nutrients, or three and a low carb meal on WS. Beware, I tried cutting down to two and a protein meal, thinking it'd speed things up buy my weight loss completely stalled that week!