Two jobs, too many mistakes

I work really hard at two jobs. I got instructions from one of my employers on a billing issue, I did my work, and found out later that I misinterpreted the instructions and under billed more than $2,000.

I’m having a lot of trouble with this in my mind. It is fixable, but I’m very concerned about how it will look to our clients. I know I can’t control their thoughts, but it becomes concerning to me when it’s my thought that it could affect how the customer perceives the professionalism of the business.

This mistake is also the latest in a series of mistakes I have made. My confidence is very shaky right now, and I’ve contemplated resigning from this particular job. I do this second job because I enjoy it, not because I need the money. The trouble is, right now I’m not enjoying it. I’m stressed and tired all the time. I’m not sure how to move forward from this – your help and coaching is appreciated.