i'm sorry you're feeling so bad.
i have fibro and ms and it doesn't sound like fibro to me either.

has your neuro done any mri's?
what does your pcp think?

do you know what your neuro exam is? does it turn up anything abnormal?

you may need to get another opinion from someone else.
maybe your dr isn't looking at you objectively anymore.

and ps on the exercise. i think it's great that you're able to do so much.
but, if 20-25" makes it so you can't walk why don't you cut back to 10-15 and see how you feel.

please keep us posted.