On probation for leaving the scene of the accident my probation officer gave me a drug test and I failed.

It is totally up to the judge, if you get a judge who does not like leaving the scene and does not like drugs, he can give you the max.

The worst, he sends you to jail or prison for the entire probation time. I would expect about 30 days in lock up, and then put back on probation, but it is just a guess.