This is extremely curious because things very similar to yours have happened to me.
First of all, I am hereditarily blind. Well, not "totally blind", but I have too little vision, basically if I take off my glasses I simply can't make out most things in front of me, I need to have them right in front of me in order to process what I'm seeing XD. There have been times when I've thought about what it would feel like to be totally blind and I really can't imagine a life without vision, I think at this point in life (20 years old) I've learned enough about what it's like to live this way to lose my vision niw. I just couldn't or can't imagine living like that.
And secondly, I also had a somewhat similar problem with your back problems. Mine wasn't severe enough to live with throughout my life, but 1-2 years ago I had a problem in my lower back that prevented me from getting up and walking completely; it was too much pain for me. I didn't go to any doctor or anything because I didn't think it was that serious (and it wasn't, fortunately) and since that day I promised myself to exercise to relieve my back and also to keep a better physical shape (something I had already been planning for months, but I never dared to do it). That was the moment where I started to appreciate a little bit the basic functions we can perform, because, like you, I wondered how I was going to distract myself if I lost my walking.
And I think that's been it so far. I'm only fairly young so I haven't experienced as many things as you have, but anyone can have a moment where they have to stop and reflect on the little things they have and don't know how to appreciate them.
Cheers!
Oh God! I had no idea you live with these problems and I'm sorry to hear that. Cases like yours should serve as examples to many. You see people complaining for this and that, yet others are living with several disabilities and are still finding a way to enjoy life.
Hats off for how you handle things and never give up! Life is life and must be enjoyed, as well as appreciated.
Thanks for sharing your story. It makes me appreciate little things more.