Herniated disc pain aggravated by driving golf cart at work... Suggestions?

I have two herniated discs that are mostly managed by exercise and diet. However, I just started a new job as a cart girl at a local country club for the summer and the pain is near unbearable. The job is so fun and is perfect while I go back to school (as a 33 year old) so I need to find a way to lessen the jarring bumps. I'm thinking some sort of a seat cushion? I started looking on Amazon but they are mostly geared for office workers. Any suggestions?