I am only a step ahead of you at this point applying for SSDI. It is SO overwhelming! I applied and just got turned down and now I am appealing mine. It's the second phase. I too had a hard time trying to explain everything to them and your story sounds identical to mine.
I am fortunate enough to have a service through the county here in MN that they help you fill out alot of the paperwork and they even go online and get it to SSDI for you. The paperwork about my daily living I had to fill out and I was "nuts" by the time I was done. I felt like pulling my hair out, and I rarely get like that!! I did it slowly over "days" because I can't write long without pain in my fingers/hands too.
I wish us both luck with this dreaded process and know I'm going through the same thing as you.