A couple of other things to consider......Did you change the strings and use a different gauge? If so, you might want to try to tighten the claw that the springs are attached to on the backside of the guitar. That will pull the trem back down. Try this anyway even if you didn't just change string gauges....

Not going against what aschleman said, but you might want to try adjusting the springs first. A truss rod adjustment is not something to just play around with, you can snap a neck very easily....but if you do try it, do like he said and only go about a 1/4 turn at a time, and allow at least 30 minutes after you make the adjustment to give it time to adjust. It's not an immediate adjustment.