I really don't know much about fibromyalgia, but I think some of the symptoms are similar.  I have always run, even before I was formally diagnosed.  I've built up endurance for a long time.  I've learned to listen to my body.  Fatigue will stop me from running before any numbness.  I've run while not fully feeling my legs before.  i've also run with half my body vibrating.  It's a very strange feeling.  It just means I have to really pay attention.

 

Exercise cannot cause an M.S. relapse, but can make it temporarily worse.  I think I am really good at paying attention to what is "just a little tired" and needing a break.  I have learned by trial and error.  I know I am lucky, but I also think I'm smart about it and make my own luck.

 

I hope it helps....Good luck.  Start slow.  Work up to it.  Pay attention to how you feel the next day.  Don't be afraid to adjust.

This is really helpful!  Thanks!

The problem with fibro is that while exercise is an essential part of the treatment plan, doing too much physical activity at once can cause a flare and result in one to several painful days in bed.   I'm starting extremely slowly with walking every other day, planning to build from there.

I can provide a tiny bit of anecdotal info.  We have a friend who was diagnosed several years ago, after months of symptoms similar to yours.  He was immediately told to cease caffeine, alcohol (specifically wine, he can drink spirits and beer), and chocolate.  That first Christmas was pretty bad!  I don't think he limits any food.

He used to be very active, but through trial and error has found the activity level that won't put him in bed for days.  One thing that he does is to take a 'nap' every day around noon for 15-20 minutes.  He doesn't need to sleep, but he needs to totally stop and let his body relax, no matter what he's been doing.

Good luck with learning to manage it.  I've seen him struggle, and come to a compromise with his body.