RGR, something I was told years ago after similar 'problem' you have to think of your energy reserves as a box with only a certain amount of energy in it. When you have used up that box, its gone, and you will be using the following days, etc etc. If you can learn NOT to use the whole box, day after day after day, things do start improving. slowly.
Initially (in my case) I worked out that I had less than 4 hours use in my box a day, the rest of the day HAD to be resting or sleeping. If I did 6 hours one day, I would be stuffed for the next couple of days, provided I rested and did nothing on those couple of days. If I tried to do more, I was stuffed for a lot longer. Think of those figures, the box takes 20 hours to give me my 4 hours use. thats 5:1. Your 'extra' 2 hours over use will take an extra 10 hours to replace, on top of the normal recovery! scary stuff.
Eventually, it improved, but even now, When run down, it comes back to bite if I dont recognise the signs when they re appear.
Listen to your body, if the box is out of energy, stop and use less the next few days!
Edited: 09/03/2013 at 13:46