I also have fibromyalgia and know exactly what you have done to yourself. My arms, hands and feet are my worst enemy especially when I over use them. I can sew for a day then I have to take one off then sew a day, well you probably know the drill.
I feel your pain and hope you can take it a little slower. I find when I am feeling really good, I forget what the pain is like until it hits me like a mack truck. Hope you are able to finish your gifts. God bless.