Almost 14 years ago I cut off my index finger while working at a sawmill. The finger was fused stiff so the knuckle was destroyed but the finger remains mangled, but somewhat usable.
First, get some exercise a little squishy ball or if at all possible some literal weight lifting for your hands, this can include the "hand-grips" or even a forearm weight.
Hand grips
http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=hand+grip
Forearm weight
http://www.amazon.com/GoFit-GF-WFB-Wrist-Forearm-Blaster/dp/B0007W2FJA/ref=sr_1_1?ie=UTF8&s=sporting-goods&qid=1288051339&sr=8-1-spell
Second, skills training. Get a darn typing program. If you used to play billiards - go play. Relearn how to do those things that you are best at, like tying your shoes and pay attention. You are going to relearn some very basic motor skills, pay attention to the way that unfolds, or has unfolded, just being mindful of the situation will help. For example, you will learn to do things with your right hand and tend to do things the same way with your left hand or vice versa.
Third, you are going to be alright, eventually you wil be surprised that it is normal.
For me personally, I prefer the thinest lightest keyboards I can find.