Lately I've been having problems hitting both backhand slice and volleys that are about face height (~6 ft.). I don't know why because I used to feel comfortable with these shots, but the last few months I have had trouble controlling them. I either hit under the ball and it shoots up high, or I try to over-compensate and hit it straight down into the net. I used to be more comfortable using backhand slice than using my 1-handed topspin backhand, but now that is changing and I actually feel more comfortable hitting the topspin shot. Its really bizarre how I lost confidence in this shot, and its not just in match play, but when I'm practicing or hitting against the wall, I feel just as uncomfortable with these shots. Every other shot seems to be improving while these are worse. What the heck is going on?