Good Luck, Pati.
It's a similar situation in the UK - where I applied for a disability benefit after a severe injury, unless you have something that is clearly and indisputably a disability you get turned down, but the rate of sucess at appeal is high, over 90%, only a subset of people appeal, so there probably is some element of self selection, but there must be an awful lot of people out there who get turned down, but who meet the criteria. I knew I did, so I went to appeal, which meant getting hold of all the paperwork, I found that both the doctor who assessed me and the forms my GP had filled out ticked all the right boxes, there just seemed to be some kind of institutional rejection process unless it was very clear cut (double amputation, paraplegia, that kind of thing). Unfortunately benefit fraud is a big problem, but when two independent doctors agreed, the mind boggles!
The nature of the whole process is having to be very clear about what you can't do and the negative affects of attempting to do some things, which is a very negative thing to do, which makes it even more distressing when having exposed yourself so much, you are still turned down. It's sad, as I know a few people who clearly should qualify, but don't even apply because the process of thinking that way and comparing how different it is from "normal", to only face rejection because of it is too distressing.
It's possible that the tests they do may not show anything like what actually describes how you function. I knew what the basic tests were, mostly reflexes and range of motion, I have normal reflexes and the vast majority of the time I have (at least) normal range of motion and I never said anything but that in the explanations of why walking hurt, but those tests had to be done and were cited by the civil servant in the denial of the claim.
So you definitely have my good thoughts because I know what a heart wrenching process it is to go through.
Cheers Anne