When the weight loss fairy comes . . .

I've been doing Body Revolution for about 2 1/2 weeks now and have had wonderful results. It's to the point where I'm almost seeing a teeny change daily. But it's when these changes happen that I'm wondering about. Sometimes it seems like I'll look at myself before bed and seem normal, then I wake up in morning and it's as if my body melted a little bit. I know that you weigh the least when you wake up and your tummy is smallest because there's no food in it, but this happens to the rest of my body too. Does this all really happen overnight? If anyone can give a quick rundown of the science behind this (if there is some). I know sleep is important for weight loss because that's when your body rebuilds, but what exactly is going on? Also, does anyone else notice this? Or maybe it's all in my head. But it still gets me all excited to go to bed. It's like Christmas in the mornings!