I'm in a prop class and I tested dirty for drugs if I go to jail when I get out will I have to start the class over

You're NOT on probation? Why then are you being tested?? What's going on here?

If you are in a "prop class" you are on probation, which means the court is not done with you yet. Call an attorney, you just cant explain or advise via txt

You are on probation or you wouldn't have to undergo drug tests. From your reference to "prop class" I suspect you are in Prop 36. You need o consult an attorney about what will happen next. My recollection is that all you get in Prop 36 is 3 dirties but I could be wrong. Get help.