Well done on working towards your goals! It is not easy and I admire you.
SSDI is much needed and saved me over the years when I could not work due to my illness. I could not have survived without it and know that many others are in the same place. I also recently went off of SSDI as well, using up all my TWP months. I am nervous about losing but it is there to refile during the allowed time if something happens if we cannot continue to work, which is some peace of mind. I hate not having the security though and I miss having my time as my own and to take care of myself, it is harder to do when working and more stressful. It is, however, nice being productive as you mention. The extra income is nice as well, but most of all I will not miss having reviews.
Best wishes as you move forward and in all your future endeavors.