A little bit of fibroymyalgia advice:

Eat Good = Good Day

Ead Bad = Bad Days

I am becoming 100% convinced that what I eat, drink, or whatever determines the quality of the day I shall have.  If I eat good and drink well, I have less pain, more energy, and at the end of the day I realize I've had a pretty good day!

On the other hand (and this is a bit unfair), if I've not been eating so well, had too much sugar, too many carbs, too many sweets, too much fast food, or anything along those lines, I don't just have one bad day, I have about three bad days.  I think this is because your body takes a while to get all of this bad food out of your system.

I'm certainly not a dietician or doctor, but I think I have the ability to think for myself.  Here is what I would advise:

Do your best to eat well and drink well.  I don't need to tell you specifically what that means; we all know full well how to eat well.  But, if you've had a bad day of eating, I would suggest drinking extra water.  It can help flush your system out more quickly, plus it can provide more oxygen to your muscles, hopefully meaning less pain.

Go to the store and buy healthy.  Don't even buy the junk and tempt yourself.  Also, take good supplements.  There are a lot of supplemnents that are a waste of your time and money.  I believe supplemnts are the other key to having a good day.

Why?  Because when you have fibromyalgia, sometimes all you want is a good day