What can I do to get my record cleared?

I received 2 years probation for a felony trying to obtain prescription morphine at a veterans affairs pharmacy. I had taken medicine and a wreck the night it happened and I don't remember doing anything my doctor said. It was an allergy med so I was put as a drug allergy at the pharmacy. I pleaded guilty even though I don't remember doing it. I had never and still have not been in trouble since. I served 1 year of the probation because the judge dismissed my probation early due to not getting in trouble again. I was 39 when I got in trouble and never been in trouble before and after. It happened in 2010. I am trying to find out how to get my record cleared so I can get my rights back. What can I do or if there is anything I can do to get it expunged?