I've been riding for a couple months now, and have experienced some numbness in my hands on my usual 20-30 mile rides. I bought riding gloves which did help a lot, but went out for 50 miles yesterday and really seemed to screw up my left hand. I finished the ride about 24 hours ago, but still can't open a jar with my left hand, and worse, I'm in a little jam band and I can't really play guitar.

Any thoughts on what's wrong? When I feel my hand(s) going numb, I try to find new positions or change my grip around, but it seems not to help.