Well it's been about 5 weeks of significantly reduced activity and i have seen no improvements in my condition. I still feel unbelievably tired (especially, but not limited to, the legs) no matter how much i sleep, or how little activity i've done. I've been feeling this way for about 3-4 months now.
Lately I've only been riding about once a week (with reduced intensity), have reduced weight training (upper body) to twice a week and i've been having at least one complete (as in not even leaving the house) rest day per week. The only other exercise i do is walk to and from uni 5 days a week (about 20-25 mins each way). I've seen a doctor and a blood test has ruled out glandular fever. The doctor suggested I take a high dosage of multivitamins. This has not improved my condition. I've come to realize that this cross country racing season is a write-off. I've read about other people who have experienced the same sort of thing continuing for months and even years.
I guess my advice to other young people (i'm 19) is that more is not always better. I realize that now, and realize that rest days are a necessity no matter how motivated you are.