Hi, Berean, and welcome! I used to live in a town named Berea! Loved it there.
Well, I take 5,500 IU of vitamin D3 a day. I do have absorption problems so I need to do this. I live in sunny Florida but still had a deficiency because I use suntan lotion when in the sun. That blocks the vitamin D from the sun from being absorbed in your system. So that, along with the absorption problem, has me taking more D. These days it is being suggested that everyone should take 2,000 IU of D a day but be sure to talk to your doctor about this. You do ask questions in your post that we can't know for sure. We are not doctors so you should talk to your doctor or your pharmacist. They can give you the correct answer to your questions about vitamin D.
I have a long list of ailments along with fibro. Sometimes it can be confusing. I do use ibuprofen with food, Tylenol, malic acid/magnesium supplements, vitamin D3 supplements, and a muscle relaxer called Robaxin to help with pain and fatigue. I do have a form of rheumatoid arthritis so this combination has helped me a lot. I didn't want to take Cymbalta, Lyrica, or Savella. Just my choice even though my doctor suggested that. I'm doing fine with the above. I also walk daily. That's a great gentle exercise for fibro. Swimming and yoga are good, too. I pace myself when doing things, also.
What works for one with fibro doesn't necessarily work for another. We have members on narcotics but when I tried them they didn't help me one iota! I had level 10 pain like you do and could barely lift my feet due to nerve pain running down my legs and hip pain. I needed two canes to walk and my strides were in inches. This all happened this past winter. But, I was put back on ibuprofen for the inflammation I was having from arthritis and then was given the Robaxin and, boy, that has made such a significant difference in my pain levels! I still have pain but nothing like what I had last winter! I still have problems with stairs but I don't have any in my home so that's not a huge problem.
I'm looking forward to getting to know you better. Don't hesitate to ask questions because we are here to help you. Hope to hear more from you soon.
Sherrine