Diversion is when lower level drug crimes(poss. of paraphrenalia, possession, under the influence) are diverted from the criminal court system into something along the lines of Rehab or something similar. The court will drug test you at random times as well.
OP, I'd wait a while before going back to whatever drugs you did. You tend to only get diverted once and after that it'll be a misdemeanor or felony charge for you.