I would suspect the likelihood exists that you were put on house arrest/home detention under what is called a "direct commitment." Should this be the case, unlike a probation violation allegation where a court date would be set to determine whether a violation occured and what the appropriate punishment would be, a direct commitment is treated much diferently.
With a violation of direct commitment the person is transferred to the jail or prison facility to finish the "executed" sentence originally imposed by the sentencing judge. In other words, an original direct commitment sentence is in effect saying that you are serving the terms of your incarceration at home as opposed to a penal facility.
As a result, should a violation be determined by the applicable home detention/home detention agency, such a report is basically telling the sentencing judge that home detention is no longer willing to monitor based upon a violation of their rules leaving no option but to transfer the remainder of executed sentence to be served within applicable penal facility.
I hope that answer helps.
It depends on the terms of your sentence and house arrest. Although your sentence can't be extended, there may have been terms of your house arrest that if violated may lead to some other sanction. Of course, the judge can make you spend the last portion of your sentence in jail.
But I think the larger question for you is the fact that despite this being your third OWI, and despite being on house arrest for almost a year, and I assume going through drug treatment, you are still using. That doesn't bode well for you staying out of jail once your sentence is complete. What am I going to do to stay clean is the more important question.