How long have you had CFIDS ? Or when were you diagnosed with it ?
I was very lucky to find a good Support group in my area and met one of the heads there, who's had CFIDS for over 20 years. She's a research expert on CFS, besides just her own full-blown experiences with it.
When I first hooked up with her, I asked her so many questions, because the dang disease changes so often.
What you're going through is the normal ups and downs of it. They call it "crashing" in CFS language. When you're more exhausted and the other symptoms flare with that.
There are over 100 symptoms that can come with CFS. Some come and stay, some come than go. It's a roller coaster ride, for sure.
It's taken me 3 1/2 years of learning about it, since it and Lyme made me homebound and unable to work any longer.
The best favor you can do for yourself, is do a search on CFIDS and research it on the Internet.
You can contact one of the CFS/CFIDS Associations and find out if there are any support groups in your area. Talking with other local people who have had it a long time really helps. But with any disease, Researching it on the web on medical sites is your best bet. The more you learn, the less shook up you get when a new symptom hits you or something changes. It's a very weird syndrome for having so many possible symptoms ... so it's good to know as much about it as you can. Then you just sort of "ride with it". Good days - bad days. And sometimes a bad crash can last for months.
You need to gradually learn your own pace. Or as they call it, your "energy envelope". It's like you figure out how much energy you can expend in a day and you learn to stay within expending only that much.
It took me two years to learn what this "syndrome" can do to me, but I also know that tomorrow, another new thing 'could' happen. I just pray for no more please.
Just rest. That's what the best researchers will tell you. Then learn what your energy envelope is.
Rest and Peace.