Thanks Wayne for your detoxification ideas, they sound like a good place to start.
Wildaisy, your reactions to B12 are very probably not detox, but the wacko B12 "startup" that Freddd discusses in his protocol. I know some people believe this is dangerous doctrine, so I'd encourage you to research and decide for yourself. Freddd's theory is partly based on the notion that anyone who is deficient in B12 will have a strong (and often unpleasant) reaction to it. My own experience is that my symptoms get worse before they get better on the active B12 protocol, which is what makes it such a rocky road. In my case, I was pretty much thrown to the ground for a couple of months, starting; now every time I up my dosage I get more crashiness, but it's kind of turned to Crashiness Lite, and another set of symptoms seem to come up for review as I continue.
Even while crashy, I've had measurable results in improving several symptoms, including ones that stuck around when I was feeling better on other treatments. And many many people, including Freddd himself, have been greatly helped after they went through the nasty bits. Freddd describes it as being like this: since your system is getting so little input, it turns the output volume on high. When it finally starts getting more input (B12 active forms), it's like what happens with an electric instrument whose volume has been turned down and is then turned up; the amplifier suddenly howls, shrieks, crackles, and spits out all kinds of weirdness until the volume can be adjusted to meet the new level of input.
I'm really convinced now that active B12 deficiency is crucial, probably primary, in CFS/FM, so I'd encourage you to look into this. I've done detoxes, so I can understand the confusion, but to me there is a difference in the quality of the effects. If you asked me what that difference was, I'd have to think hard before I could articulate it, but I can feel it.