For the most effective means of reassurance, pick up some THC test kits and test yourself. Be sure to use the first urination of the day.

Dump the magic detox potion. The efficacy of magic potions have been addressed many times throughout the DT forum. Do a forum search, using the terms "detox products scam dilution"

Drinking a bunch of water in the days or weeks before a U/A is of no help. To find out why, do a Forum Search with the terms "water soluble"