You have ably demonstrated that you are an addict. You have blown the breaks the court system gave you. I agree that inpatient treatment is an excellent plan for your immediate future, which will make it much easier for you to achieve your "many future plans." But you should get a lawyer to represent you on the revocation of your diversion. When you entered diversion, you signed some sort of contract explaining what could happen to you if you violated its terms. (A court is not require to revoke, but the fake urine on top of the dirty u/a would like lead to revocation.) A lawyer can help you coordinate the court hearings with any treatment program you can enter, and be able to use your commitment to being clean and sober to the best of your advantage with the court. Ultimately, the court's goal is to get you off the drugs -- and that's an excellent goal for you to share. Get yourself a lawyer and discuss your options.
If the court chooses to revoke your diversion, which seems likely in this case given the facts you have described, typically, the next step involves the court reviewing the police reports submitted in your case and making a determination of guilt based on those reports alone, WITHOUT A TRIAL. Most diversion agreements involve some kind of stipulation to that effect. Once the court has found you guilty, they will sentence you based on your offender score. If your conviction is for simple possession and you have no prior history, the standard range is 0-6 months. Checking yourself into an inpatient treatment program voluntarily might look good to the sentencing judge, but there's no guarantee it will make any difference. The court would be within the scope of its discretion to order you into inpatient treatment anyway, so that's likely where you're going to end up, regardless. What you are going to need at this point is an attorney. Trying to handle this on your own will almost certainly result in you getting a far worse punishment than if you did the smart thing and hired an attorney to represent your best interests.