Energy Low--Can't identify the problem

[Eden]

I'm probably repeating a lot of what Malliotpois said but,
It does sound like you are having some over reaching / over training problems. Take a few days off - maybe even a week. Rest up and eat well. Then get back on your bike and see how you feel.
Make sure that you eat and drink on the bike and make sure that you eat within a half hour of getting off the bike. You don't have to use a recovery drink, but if it is difficult to decide what to eat or make something they can be great for getting the right balance of carbs and protein in quickly.
When you are training make sure that you aren't doing hard workouts every day of the week. Take at least one day completely off the bike and make sure that several days on the bike are recovery days (hr zones 1-2 only!). Make every 4 weeks or so a recovery week - take more than one day completely off and make all the other days easy.
If you don't have one purchase a hr monitor. One of the signs you are overtraining is an elevated resting hr, so start taking your resting hr and keeping a log.
oh - and just food for thought - I have a coach and none of my training is tracked by mileage, its all tracked by time.