Situations like yours are what people who get off on "tough on crime" policies and push for harsher punishments for "bad guys" never stop to think about. We need judges to be able to consider an individual's unique circumstances in order to get justice, and the same is true for HR departments. Blanket polices that simply send every resume to the bin when the applicant has been arrested and/or convicted with no regard to the situation are just stupid.
You never should have been behind bars, but having served your time, you should have left with a clean record and the opportunity to rebuild your life.