It is extremely unlikely that you will lose your dusability over this. You did right to report it.

Fill out the paperwork they sent you, emphasizing the continued difficulties tgat your diagnosis is causing you.

I guess, by now, you've sent back the paper. In filling out a paper like that, you can put down how you were unable to cope with that job in January. Even if they didn't specifically ask you that, you can put that in there.