Oh hon, I'm sorry you have CFS. I was diagnosed with it about 1t years ago. I would not wish this on anyone.
Not sure I'm going to be helpful with tips, but here goes....
I try not to judge what I can do one day by what I can do on another.
I try to give myself "permission" to have days where it's all I can do to drag my butt from the bed to the sofa.
If I know there's something I have to do that's going to knock me off my feet I give myself time off afterward to recoup.
This going to sound odd, but I give myself permissoon to climb on the pity pot once in awhile. There are days I'm just overwhelmed by the unfairness of it (I know life ain't fair). So I give myself a certain amount of time to be pissed, hurt, down, whatever about it. Then I make myself climb down off the pot.