Hope I understand your question. are you asking about disability? You can file for SSD or SSI, if you have fibro. Once you are approved there are lots of rules that restrict your ability to do most any type of work without notifing the SSD office and filling out more forms, and watching the income you make so you do not go over a certain amount and thus loose the disability payments.
Why did I tell you that? To let you know that disability payments are figured by what you have paid into the system and if you have enough work credits on your record that alows you to even get disability. If you do not have enough credits for SSD, then depending on your household income you may qualifty for SSI instead.
I am on SSD and I had enough work credits to apply for disability, but I did not qualifity for SSI, so my income is very low. What I am trying to say is the longer you can work the better income you will get. There are lots of jobs that can be done at home, and provide you with a good income. Read day 7 of my blog, to get some ideas on places to look for work. I know lots of you are very bad off, but if you can still use a phone and hear well there are lots of telemarking jobs out there that can be done from home and you can set your own hours to work.
If your brain fog is bad then fibro has become a real disorder in the eyes of SSD and it is worth applying and maybe you will get lucky in applying for disability.