I have my tribunal hearing next Tuesday, I got hold of my medical records once I decided to appeal,your post has just told me that I did the right thing; if I were you, if you haven't got any professional help, get it now from CAB or the likes, ask your doctors receptionist for a copy of your records going back to when your illness started, you may have to pay for them, but hopefully it will be worth it, and, NO-ONE ever advised me to get medical records, but I think it would be good advice to anyone going to appeal.
Good luck