You can tell a good person by what he does when he thinks no one is looking. I guess I'm not a very good person. I try, but in this case I caved to temptation.
One poor choice does not reveal your entire character. The fact that you feel bad about is telling. If I were you I wouldn't do it again and just don't dwell on it. Learn from the mistake.
People's comments here can come across as very harsh sometimes, but by and large they're well intentioned.