on-and-off for the past couple of weeks i've been feeling a little lethargic from the time i wake up till the time i go to bed. this is a bummer b/c i've been building the miles pretty steadily lately and i constantly have an urge to be on the bike. i'm wondering if this could have anything to do with getting too few calories?

It would make sense because it seems to go in cycles: i get tired, i ride less, i feel better, i ride more, i get tired...

i know there are tons of things that could be dragging me down, anyone have any thoughts?

protein? carbs? vitamins? cross-training? intensity? I'm all ears.