What can I do to help with this?
I’m sorry, but there isn’t anything. You just have to give into it.
I suggest having wonderful sheets. Soft, cotton sateen or Egyptian high thread counts, over 400.
Dark rooms. Nice scents. I like lavender. Make your bedroom,
a place comforting and welcoming. Best room, in the house! 
Learn to pace yourself, that’s all you can do.
Fibro is all about exhaustion and when you hit the wall, that’s that. shrug. Be gentle and kind w/ yourself.
Excercise, or rather, movement will help. Do what you can and nothing more. Listen carefully to your body. Things like stretching or even just raising your arms over your head count. Walking any distance - around the house… around the living room. If you can’t do that - and yes, there will be days, and days… Try doing some of the yoga breathing exercises.
I find that supplements like glutathione or choline will give me an energy boost. Red Bell Peppers!!! Yummy with a boost. Also, cutting out sugar completely and sticking to a super healthy diet has done wonders for my energy capabilities.