First off let me say this.Blocking isnt a skill,its a desire.Sure you can let it by and let the Pitcher get a wild pitch,or you can have the desire to win a game and put your body on the line!I had this same problem roughly two years ago massey,heres what I did
-Did dry blocks every night(start in catching position,drop to blocking position,pop back up into catching position using your legs not hands.)Not only did this get my form and repetition down,it also made me quicker.
-Throw baseball at your chest protecter,dont try to block or move,just let it hit you.When the baseball is hitting your chest protecter directly and you realize the ball wont harm you,you somehow get a mentality of"I can do this"
Finally remember this in games.You block a ball,not only does it stop runenrs from advancing,it somehow always saves a game.Letting it by you gets the run in.
Pain is temporary,pride is forever.In 10 years you wont remember you had a little bruise on your thigh or arm,you will remember you won state because you had a game saving block
Good luck bro