Simply put, yes. However, your probation officer will more than likely use your first UA sample as a baseline. As long as your levels are going down in the future, and your urine is not dilute, you should be okay.
Yes you can be violated. The PO can drug test you at any time and they will. It's best to stay clean at all times while on probation. Most POs and judges are not going to believe that you though that you could smoke dope while on probation, so its not a violation because no one told you. Additionally most drugs do not say in your system 2 weeks so if you test positive, the PO will know you used while on probation.
Cannabis can show up in a urine test for quite a long time under certain conditions. Your probation cannot be violated unless they can show that you consumed cannabis after you were placed on probation. Hopefully you did not make any type of confession. You need to hire a lawyer that understands the scientific factors involved. Most attorneys do not. If you kept quiet, you could have a very strong case
It order for the state to successfully prosecute a violation of probation, they must show by a perpondence of the evidence that the violation was willful and substantial. In your particular case a lot will depend on the nature of the drug that you expect may show up in your urine screening. My office routinely handles cases in Sarasota and we have offices in Bradenton and Sarasota. Feel free to contact me with any questions.