I was in a similar predicament, I am diagnosed with autism. In my first attempt of A level, I failed them all. In the end, I passed them, but with terrible grades, only one C grade. This was all despite achieving 4A* and 6A at GCSE.
I kept trying basically, and with jobs it was the same, I now have schizophrenia which makes life even more tragic when compared to non affected individuals to some degree. My only suggestion is to keep persevering with whatever you set your mind to and remember change is not giving up, sometimes change is necessary. After gcse' i wanted to be a dr, after failing first a level year, i decided physicst, now i'm on way to economist. keep trying