"i was arrested about 2 years ago for offering someone underage a beer. was a class A misdemeanor. corruption. received 5 years probation. been almost 2 years now. all costs were paid off. stayed sober for the whole time. recently i slipped and had a few drinks with a friend. got pulled over. blew a .145. what is gonna happen? will i have to go to jail? for how long?"

Totally up to the judge, since your PO has not violated you yet ( will assume you told them ASAP, since not telling them is a much more serious violation than the actual ticket for DUI

But first you have to also deal with the DUI that may give you a few jail days depending on the judge.

But yes, you could go to jail for up to the entire probation time, or just a few months ( or be given a very serious warning and put on tighter probation.
It is totally up to the judge and their rulings are not consistent