If I was just jailed for 30 days on a VOP, is my probation now terminated?

This will be up to the Judge to determine. Sometimes a Judge can sentence you to a certain term of imprisonment (i.e. 30 days) and close out your probation so that it is officially terminated, or a Judge can sentence you to a jail term and continue you on your probation. My advice is to contact your current probation officer to see if after your 30 day sentence is your probation closed out for good or if you are still on your probation to avoid any future violations.