I don't think there is a right or wrong thing to do. Seems to me you did what was best at the time for you & your child. Like Cranky Kitten and TFB said, being a mummy isn't perfect all the time, occassionally the settling techniques won't always work but that is the minority of the time & what more can you do? Nothing, nothing but walk away like you did, regain composure for your sake & the sake of your child/ren.
Could you be taking on a little much with all the classes & seminars? Do you need to step back and just be at home and be in the moment, whatever that may be?
From your post, you seem (and this is only me looking from the outside in) that you are placing alot of pressure to be a 'perfect' mummy (no such thing) and do everything 'right'.