The light levels are pretty good in my room, especially in the afternoon. I'm in the middle of the summer where I live so I get plenty of sunlight, and even in the winter the lights in their cages are pretty bright.
My bearded dragon is doing the exact same thing. She just brumated in the winter and now she's acting lethargic and not eating. If I take her out and move her around she seems to become alert again for a little bit, but then she just goes back to sleep.