whey keeps me up sometimes, even the whey in milk protein isolate like in MD will do it to me. i use cottage cheese instead, less whey, and makes you feel fuller. if they whey doesnt bother you try mixing them it tastes good with chocolate MD, since it sounds like youre just hungry.
or since youre low carbing anways, switch around some fats from during the day and add to your MD, a couple of teaspoons of whipping cream (what 10g of fat?) in a protein shake should do the trick to fill you up and induce a little food coma.
odd train of thought you have, you changed your diet, low carb, and now have trouble sleeping, instead of changing your diet so you can sleep, you want to take a supplement?
adding 200 cals of food before bed to let you fully sleep is far better when youre dieting than staying in what ever calculated calorie range you have going on and not sleeping well, for a lot of reasons.