Something else... you seem to be pretty static when you "shadow box". You are suppose to move around when you shadow box, like this (0.00 - 1.35):http://www.youtube.com/watch?v=JbRykf-5Zo8&feature=related
A rolling stone gathers no moss, or gets smacked in the chops. If you are standing in more or less the same place and not moving your body, you are going to be easy to hit. If you are just practicing punching (and not very well at that) during shadow boxing, yet keeping your body in the same place, you are not vizualizing being attacked or thinking about it. If you are not thinking about someone else hitting you back, what are you going to do when someone is in front of you, hitting you back?
I'm thinking you haven't done much in the way of sparring or fighting, as this is a really basic thing to learn. Anyone who stands still, regardless of striking discipline, is going to get hit... a lot. If you don't move around when you are "shadow boxing" when are you going to train moving around? You will fight the way you train. Its your a$$ though, so do whatever you want.