We process protein at a higher rate than healthy people do. Try eating or drinking some protein every 2 hours, 80-100 grams daily.

My doctor presecribes me a high dose Vitamin D that i take once a month. It has helped a lot with the fatigue, i wish i could take it more frequently (i have energy for 2 weeks after taking it).

I dealt with Fatigue by ensuring I get a good night's sleep. This means I must take Lyrica & Neurontin each evening before bed.

I have no magic answer, I just plop in bed and ride it out. For me pushing myself past good sense just made it last longer.
You might consider the fact that you might also have chronic fatigue syndrome. 70% of the people with fibromyalgia also have CFS.
I know I have both because exercise activates a flare with extra additional pain. However fibromyalgia alone benefits from exercise.
Everytime I try and start a physical theapy program I end up crying mid session because of unbeatable pain. I mean baby stuff, and mild stretching.
For me finding a warm pool to walk in is manageable.

Nothing has worked for my fatigue, but least I found something which helps with my pain and stiffness. I tried sleeping tablets to get a good night sleep, but has terrible side effects and vomiting/diarrhea so no trying them again.