What people knowledgeable about nicotine addiction would call it is a full blown, 5 alarm relapse. The term "slip" minimizes what has taken place. By taking even 1 puff you have awakened your addiction and given it strength that your hard work over a year and a bit had taken away. I'm sure you are feeling that over these past few days - urges to have "just one more" are no doubt stronger than they have been in months. Statements such as "Complete and utter disgraceful failure to mankind" are simply childish - grow up!
I'm glad you have reaffirmed to yourself that smoking is nasty. That's something positive. I would be concerned about not knowing the trigger that lead you to make the decision to have that first smoke and YES, that was a conscious decision YOU made - no one else. If it was just "a slip" then why did you have 6 cigarettes over 3 days? Why not just the first one, or maybe two?
You have talked a lot over your time here about not wanting to fall victim to some horrible smoking related disease. There's only 1 positive thing you can do to try and avoid that outcome and that is to take quitting seriously. If you don't learn something very significant from this episode then you are bound to repeat it next time something unusual happens.
Remember; it was you that said: " I have no clue what the trigger was."