Your job sounds too intense and "on-demand" for a return.

It seems as though you have little control over workload as you are serving customers which needs to be done well and you need to think quick.

In my job as an accountant I don't really serve anyone and just compile info for others. I have weekly and monthly due dates so I have the luxury of scheduling out my work a month in advance.

During our annual audit the auditors were present for 3 weeks and I would have to respond to their questions on-demand and get answers quick which triggered my symptoms big time.