That is good news -- damage progresses with pain, from the fingers and hands into the wrists and forearms. Try wearing wrist splints at night when you sleep, to keep your wrists straight. That should help prevent the numb fingers. Don't wear these during the day or your wrists will weaken!
At work, think of posture, lifting with your abs and dropping your shoulder blades down your back, like you want to put them in your rear pockets.
See if you can find an excercize physiotherapist to help you understand muscle (im)balance. You said it started when you were lifting weights. You've probably got some powerful muscles that aren't balanced by equally powerful opposing muscle groups.
Common problems are weaker triceps than biceps or the muscle on the topside of the forearm versus the underside. Also the rhomboid (upper middle back) muscles may be out of balance with the pecs. You need a pro to help you find your issues.
Does your gym have a device that allows you to "roll" a weight up on a bar, with the weight hanging at the end of a rope? If so, start with a *very* light weight and roll it up and down, using overhand action to roll the rope over the top of the bar, then unroll. Next use an underhand action to roll the rope under the bottom of the bar, then unroll. Start slow -- you want to strengthen it gradually so you don't aggravate the condition. After doing this, you may want to ice your wrists, as described earlier, to avoid inflamation.
A final thought. Consider balancing your weight workout with yoga or another type of whole body strength and flexibility. It may help you avoid injury later.