If I don't take muscle relaxer at night, I'm up multiple times with cramps in my feet & calves. That's on top of magnesium and using heat.
Fatigue is a whole different issue. Still working on that.
(B12, coq10, avoiding sugar/gluten only helps a little)

I understand how the fatigue can be overwhelming. There are days that I am just thankful that I was able to get up and shower.

Yes, studies have found that people with fibromyalgia have 3x the tension in our muscles compared to people without it. I find that topical magnesium can help tremendously (my favorite is Theraworx foam), it instantly stops cramps so it can really help with the tightness and pain. Heating pads can help a bit too. I'm yet to find something that makes a significant difference in my fatigue though (some supplements like B12 and CoQ10 can help a bit, but my fatigue is so bad that not much makes a dent in it).

This may not apply to you but I thought I would mention it. In my case things I eat contribute to cramping. I cannot have various kinds of sugar including fruit or any kind of fruit juice in the afternoon or my legs will cramp up. This may be a different issue for you, I'm just talking about myself. My PCP said I should take electrolytes but believe me I know it's not electrolytes that I need because of all the things I take but maybe some people need electrolytes so that's why I am mentioning it. Some people need a lot more water and they definitely need electrolytes that do not contain sugar so I am not speaking about gatorade. Gatorade is not a good thing to take.

Thank you, Cathy, for sharing with me. I just wish they had a magic pill that would address all of our symptoms. The Duloxetine works really well on the majority of my pain, unless I over do it. I just can’t shake the brain fog, cramping, and fatigue. The fatigue is horrible. I have begun falling and losing my balance easy. I pray you have better days ahead. 💕