You seem to be off balance. You're not establishing a good stable base to hit from. You need to be set up and firmly planted and balanced before swinging. You're not doing this so when you swing the momentum is carrying your body all over the place. Your left foot is doing this little skip thing as you swing.
Look at this nice djoko sequence here. notice how he gets set pretty firmly before he swings and after contact he's still balanced like nothing has happened at all. http://www.youtube.com/watch?v=iaJrIzLb1Ko&t=43s