As I understand it, you had a VOP and so your probation was extended another year, and now there is another VOP for the dirty urine test. Is that right?
Even a "technical" violation is still a VOP. It is impossible to say the "chances" whether you'll do jail time, but it is a very real possibility considering that not only is it a violation but it is a second one. A lot will depend on the PO's recommendation.
This is not to be considered legal advice nor does an attorney-client relationship exist.
If I understand correctly, this is a second violation. The first time your probation was modified and extended.
This time the allegation is that you admitted drug use and a likely positive urine screen. This is not a new law violation and is again "technical" but that distinction has limited application (in youthful offender sentences).
The chances of jail time go up significantly on a second violation. On the bright side, you've done fairly well on probation for three years. Too many factors go into what a potential sentence might be to answer here.
Lastly, I must note that I all too often I hear about a violation and a jail or prison sentence after a minor financial violation and a lengthy (here 50% of the original time) extension of the probation. I wish you had consulted a lawyer back then!