Months late, but in case you see this:
Ever seen this? It's very common, probably on a lot of the threads:
www.butyoudontlooksick.com/wpress/articles/written-by-christine/the-spoon-theory/
This got me into energy accounting, and I started separating everything I did (EVERY. THING) into energy giving (rest), energy using and energy neutral. And then keeping track of what I was taking out of the budget and what I was putting back in. I realised fast that on a bad day watching tv, surfing the net, typing, washing up, all that kind of stuff, cost energy I didn't have. I did have to build in a couple of scheduled short rests (laying down eyes closed) for 15 mins to balance the books. I've gone out to the car on breaks at work for 15 minutes laying flat on the backseat, eyes closed. It helped, I was on the edge of bedridden at the time. It's beyond annoying to have to limit myself but if I don't I'm sorry afterwards.
The only thing that controls the pain and tiredness for me (Fibro on top of other things) is keeping in the black on that budget and thinking of it as a budget. If I get 'overdrawn' then the pain and flare pay back on the interest is bad and it takes days to rebalance. And there's the basic chronic illness stuff that also helps, like keep the freezer stocked with good quality stuff that just needs defrosting so no cooking on a bad day, dry shampoo (I could not survive without that stuff) and even paper cups and plates to save a bowl full of washing up on a bad day.
Think about diet, especially in bad patches, and see if you can find things that help. Carbs can flare me badly if I'm in a less good patch, and small frequent meals use less energy to eat than large ones. Easily digestible or very soft foods also don't use up a lot of energy to digest. (I make a lot of home made soup and stuff it in the freezer.) Sounds ridiculous but I find tv channels with adverts drain energy and increase flares on bad days as they're loud, bright, fast and unpredictable and fibro often causes hypersensitive vision and hearing. Keeping the house quiet and calm and keeping upbeat or relaxing dvds around also helps, stress and agitation burns energy and it's very very hard not to be stressed when you're in a lot of pain. I also find the only major pain reliever for me is moist heat, like a shower, bath or beanbag microwave pads, and do them morning and evening needed or not. That seems to keep pain from building up.
I found it useful to write and keep a 'plan' of all the things that help on bad days, all the things I can do that I know help. Often on a bad day when I'm badly brainfogged I don't remember what to do or how to feel better and it helps to have something written to follow.