If you are found in violation you very well could be incarcerated immedialty after the hearing. However it is impossible to say what will happen with certainty, without knowing what you were on probation for and what action or inaction constituted the violation. It is critical that you get an attorney as soon as possible. If you are unable to get one by Wednsday then it is possible for you to ask the judge for a continuance but he or she will want to know what you have done to retain an attorney since you received notice of the hearing.
This information does not create an attorney /client relationship and should not be use or relied upon to make any decision in your case. Only consultation with your own attorney can provide you with the advice you need for your case.
Depending on the violation, the judge could incarcerate you right on the spot. Be prepared and take a lawyer with you.
If you found this answer helpful, let me know by clicking the "Mark as Helpful" button at the bottom of this answer. It’s easy and appreciated. This answer does not create an attorney/client relationship and is for informational purposes only. More importantly, the information contained in this answer should not be relied on without first consulting with an attorney who practices in the related area in the related jurisdiction.
In addition to the above, it is important to know and understand whether you have a Level I or Level II hearing scheduled (also called Gagnon I or Gagnon II hearing, based on one of the court cased in which the Supreme Court addressed required procedures for VOP cases). At a Gagnon I hearing a master or conference officer will determine whether there is sufficient evidence/cause to move forward and schedule a Gagnon II Hearing before a Judge. As the previous answers explain, you could be taken to jail upon completion of the Gagnon II, but each case is different, based upon your overall record, the crime for which you are on probation, and the type of violation. In any case, you should not appear without an attorney. Best of luck.