I would highly recommend you contact a good criminal defense attorney in Douglas COunty. In most jursidictions probation is considered a break and now by commiting a new law violation you have not taken advantage of the previous break the State gave you. So yes jail is a possibility how likley depoends on many factors.
You need to consult with a defense attorney experienced in the court where you were originally sentenced (Douglas County) to probation (if you hired an attorney to represent you on the original charge, you may want to call him or her first). The probation violation is likely to be much more serious than the penalties for a second arrest for misdemeanor possession, depending upon how much time you have left to serve. Usually a probation violation requires a local attorney who can advise you on what a specific probation officer will allow (walk in, arrest, etc.), what probation is likely to recommend to the judge and what your judge is likely to do with it.