Buff but bummed

Okay, so I've been working out like crazy for a month now.  I've earned praise from my automated coaches on Wii Active ("Keep this up and you'll be coaching ME soon!"), I am now familiar with the elliptical downstairs and have managed to get to three bars into the "weight loss" category - I've even developed considerable arm muscle mass and slimmed my legs.  My blood sugars rock. My body moves without complaining too much and my balance has improved.
So why oh why am I spending the REST of my days in sleep or sluggish brain death? I should be getting peppier as I go, as I lose weight, gain muscle - but instead I slump and collapse after lunch, sleep for hours, wake for dinner, sleep more.

And worse, despite the muscles, lifting groceries is still so difficult. Doing housework seems beyond me.
I know my body is getting in shape, but something in it isn't getting the memo. Although I can see slight improvements to stamina, I'd expect more after 30-60 minutes of exercise almost every day for weeks.
All I can hope for is that with cooler weather, all this work will show. And nap to extremes now.