Are you lonely? it sounds as though you don't have any friends you can talk to about this. Still, I guess the fact that you are talking to people here is a good start. Maybe now you have opened up about this, now you can seek some professional help? There are, as someone else mentioned ergonomic ways around this, if the CT is the main problem here & not your own mindset. There are, after all, people who have no use of their hands at all who use computers. Imagine if Stephen Hawking had given up when he started with his disabling condition? I know when you are depressed reading & hearing stories of people who strive uncomplainingly & achieve bravely in the face of adversity is even more demotivating; but we are all rulers of our own destiny & we have a choice. I know I often make bad choices & figuratively beat myself up but ultimately I made the decision & the outcome is my fault. The only thing we can't change about ourselves is the past & our heritage. If you have CT it is probably a hereditary predisposition exacerbated by poor posture, use of keyboard, incorrect workstation set up etc. You need to rest & limit your keyboard use & maybe consider surgery. Has anybody formally assessed you ergonomically? Many years ago i was conducting workstation assessments the office in this scenario were 90% in their 20's & early 30's they were like contorsionists! I could barely believe what I was seeing - lounging side ways on to the desk, sitting with legs tucked under them, telephone jammed under their chin whilst they typed or filed their nails etc. to name but a view. Of course they all had the same responses when the prospects of future musculoskeletal injuries were pointed out to them - "it won't happen to me!" We may think we are working correctly but an observer can often point out things that are making your problem worse & these can often be easily rectified.
You are no where near old. To say so is an insult to us not so spring chicks! You sound sad & may be depressed. Having experienced depression most of my life I know how self limiting it can be and would strongly advise you to see your doctor for help. Get off the computer & have some fun. Meet people, travel, get a pet or volunteer. But do something to shake yourself out of the mindset that your life is hopeless, don't overthink everything. Try saying "Yes" more often, its so much more positive & cheesy though it sounds - happy attracts happy!
I wish you well.