That's the honest end of it. What you described is basically what any healing process feels like with alchemical help or without it. You come out the otherside better for it but the experience itself will be painful. Those who get the most benefit from plants describe painful purging. You may have had an altered state of consciousness but it wasn't that high feeling like you had a few pints.
The high feeling me thinks is from the ego being satiated and self gratified for a time. The addiction aspect is the ego requiring that self gratification over and over. Like any other addiction.
The point is to come out the other side being able to feel 'high' without any chemical assistance.
At least the ground work and potential for that is brought to the surface instead of being buried under dense pain. I extraordinarily doubt any plant out there causes a state of insta-enlightenment but if you experience healing one has become a better vessel for enlightenment to occur.
Insta-enlightenment is a construct of the ego, the same sort of mechanism that caused all the furor over 12/2012 where everyone thought they'd wake up on 12/22/12 in a state of perfection. A lot of people were addicted to that idea for sure.