Hi asides: I'm certainly no expert at all on this. In fact, I'm still working on finding solutions to my fibro-related problems. But, one thing I've done is to scale back, either a little or a lot, when it comes to things I 'used to do.'
For example, maybe next time you want to get together with a friend, you could drive only a half hour and your friend could drive a bit further. Or, you could do some shopping or see a movie at the half-hour point, if that's possible.
Is there an antique shop or hobby store or ?? store between your home and your friend's? Any new place to check out for a short time?
Also, it helps to cut back on the time spent together so you don't get too tired or achy. Maybe "just" have lunch together somewhere or "just" see a movie, then head back home. If it's a good friend, I'd guess she'd understand (though not every friend does, as you've likely seen).
I've been burned a few times too, like you, when I overdid something, trying to be 'nice' and I hung in there a little too long, paying for it later. It's not worth it. Simplifying life seems to be a key component to dealing with fibro, in many ways.
Hope this helps a bit. Best wishes and I hope your pain and exhaustion exits soon!