I feel for you. I have had my other hand really screwed up this way, several times since age 21.
There are many ways that nerves can become irritated; it doesn't have to be carpal tunnel (in which inflamation, or scar tissue, inside the nerve channel in the wrist pinches the nerve.) The symptoms of numbness and tingling in the hand can even result from irritated nerves elsewhere such as the shoulder or forearm. In my case, it was the shoulder and wrist, and my PT had me change my desk, chair and posture, and I improved.
WIth that said, I'm not a doctor and I'm only talking in terms of what I guess from my own experience. It's probably not arthritis unless your body has really decided to stop maintaining healthy joints. More likely you are doing more injury than can be healed each day. And it is probably something that can be helped by altering behavior.
In _Repetitive Strain Injury_, Deborah Quilter writes about people in many professions learning to do ordinary activities in ways that reduce the stress that creates soft tissue injuries. It's a common misconception that all of these symptoms point to diagnosis of carpal tunnel and then surgery to remove scar tissue.
You can do a lot to help yourself by getting a hold of one of Quilter's books, or Dr. Pascarelli (MY doctor/surgeon sees RSI often and did not even know of these books written for patients! He refers to therapists; I believe OT more often know of these books.)
Unfortunately, you may also get angry like I did when I tried to make some lists of what I could change. How am I supposed to get through the day? I know from your posts that you have a lot of responsibilities
My strategy has involved using my BPI affected arm for things I would do with my other arm automatically. Beginning with the obvious: opening doors. I also avoid many things I used do like video games, air hockey (OUCH), hammering nails. Then there is dividing heavy loads into smaller ones, such as in shelving one book instead of a fistful of books all at once, putting away the dishes differently to avoid stress, opening drawers differently. (And yes, I fear button fly jeans. Some brands are just easier to button than others.)
I also avoid certain computer keyboards: Dell in particular ships horrible keyboards. Since I am a computer professional this is critical; I use exclusively MacAlly Icekey scissor switch style. I do not have a great mouse solution at this time (though the IceMouse was pretty good.)
For relief, I regularly carry around a cold soda can in my hurting hand. It's innocuous. In 3 years nobody at work has ever asked me about my issues. I use Aleve when it gets really bad (damn those Vioxx lawyers), but I try to have drug weeks and no-drug weeks. Overnight I get some recovery using a fuzzy splint. (
http://www.hely-weber.com/)
I imagine that I have a limited budget for my hand, and I have to decide how to do tasks more cheaply (less damage) or not at all (like video games) to make room for the stuff I have to do (like work).
I realize you're in a tough place here, with limited resources. So my best ideas are, you can help yourself by going to the library or bookstore, and examining your own activities for stuff that you can change to avoid injury.
The good news is that you can recover. I wish I could believe that while I am at the bottom of final exams week with no escape, and just unpacking my book bag at school is a trial... (and "Professor, I injured my arm while studying.. can I write the exam tomorrow?" doesn't work.)