Where do you get the high quality weed?

I keep wondering if the insanity kicks in to prevent me from continuing to take herbs (or whatever) when a colony of the stuff that I am working to clear out of my system is about to spontaneously die off. When I first started this everyone kept telling me to go very slowly. I once felt really close to attaining the peace that passes understanding when a voice said "Watch out! They are going to try to take you out with them!" I was jolted awake by the fear of death and lowered my dose the next day. I have no suggestions, just trying to find the courage to keep on doing what seems to be working instead of quitting.