http://www.amazon.com/Its-Carpal-Tunnel-Syndrome-Professiona...
which, let me tell you, you should do at the first sign of pain
Do that. REALLY REALLY do that.
Also, this book is superb:
http://www.amazon.co.uk/Its-Carpal-Tunnel-Syndrome-Professio...
Also, this book is very good and covers a wide variety of bases to help you understand your problem:
http://www.amazon.com/Its-Carpal-Tunnel-Syndrome-Professiona...
This book has been useful to me:
http://www.amazon.com/Carpal-Syndrome-Therapy-Computer-Profe...
And in it they mention that some people do all the wrong things and never seem to get RSI. Better not to count on luck, though. I now wish I had taken preventive measures much earlier. I have my first physical therapy appointment next week...
If your muscles and tendons are struggling, the last thing they need is more to do. I would strongly recommend doing whatever you can to give your hands a break for a while, and then start strengthening. And for giving your hands a break, you should absolutely feel justified in getting whatever ergonomic gadgets you think will help.
If you are suffering from numbness, that means your nerves (ulnar nerve, etc) are irritated. There are indications that this is not just a hand problem, but is due to postural problems in the upper back and neck from sitting statically in front of the computer for long hours. Google "thorassic outlet syndrome".
I highly recommend you check out the following books:
"It's not Carpal Tunnel Syndrome", http://www.amazon.com/Carpal-Syndrome-Therapy-Computer-Profe...
"Trigger point therapy workbook", http://www.amazon.com/Trigger-Point-Therapy-Workbook-Self-Tr...
I give these books a lot of credit for my almost complete recovery.
It's funny, but the RSI book a friend recommended to me is titled "It's Not Carpal Tunnel Syndrome!":
http://www.amazon.com/Carpal-Syndrome-Therapy-Computer-Profe...
Contrary to the title, the book doesn't rule out the possibility of carpal tunnel, but it correctly points out that carpal tunnel only applies to a small set of RSI-related symptoms. I found the book helpful.
I too had debilitating RSI, leading to needing wrist braces and typing with a pencil lodged in my left hand and a few achy fingers on my right.
The book "It's Not Carpal Tunnel Syndrome!: RSI Theory and Therapy for Computer Professionals" [1] really opened my eyes on how to treat it.
I didn't start weight training, but did spend at least 20 minutes a day on trigger point therapy between my shoulder blades and elbow crease. That helped the most.
Then a vertical mouse, split keyboard, ergonomically placed chair, and correct table height helped prevent the recurrence.
[1] https://www.amazon.com/Its-Carpal-Tunnel-Syndrome-Profession...