If your on probation, public intoxication could be enough to revoke your probation.
There is a not a huge difference, in fact it's a very fine, sometimes grey, line.
Techinically anything that is punishable by less than 12 months in prison is still a misdemeanor. A year in prison is still pretty serious. The President of the USA can be removed from office for a misdemeanor.
The larger issue for the OP is what effect this will have on his probation, and any criminal conviction, including misdemeanors, can trigger all kinds of things including automatic revoking of probation and ordered to jail for the full term of his orginal conviction. That would really **** for something as stupid as this, but the law can be stupid sometimes.
http://en.wikipedia.org/wiki/Misdemeanor