I used to have a group above superadmin but realised how stupid I was for doing so due to the fact that there is more to it than just the ulx permissions. What I have done now is create a group with the same permissions but inherited from the group below superadmin. I have then on the scoreboard made the group superadmin show as Owner and the group that I have called 'superduperadmin' and that shows as Super Admin on the scoreboard, this rank is for people that I feel deserve superadmin.
With regards to getting your permissions back, I think you need to type in the server console:
ulx groupadd superadmin
then
ulx groupallow superadmin "ulx groupallow"
not sure about this next one, but think its something like this?
ulx groupallow superadmin "ulx managegroups"
EDIT: in the console type and look for something similar to the below command
ulx help
It will probably be worth waiting for someone who actually knows what their talking about but I just wanted to see if I could help
Owen