It's hard to explain...we have nothing like that in the US that I know of. But basically, there is a doctor that deals with any work-related injuries, burn out, etc. When you call in sick, they call you to check and see what the nature of your illness is, and they also make sure you aren't milking the system, calling in sick for fake illnesses. Some people call in sick for a hangnail, you know? So they call to check and see if it's a work related thing, or if it's just a bug or something more long term that will keep you out of work for a while. And if you have a burn out, you meet with them periodically, check in to talk about what's going on. DH had a burn out when I was pregnant with DD. We were in the process of moving into our own house, I was pregnant, the company he worked for was unstable and he had been afraid he might lose his job, his dad had something...I don't even remember what, but there was just a bunch going on, so he got leave to sort through it all, and he had to meet with this doctor now and then and that doctor worked with DH's employer to determine how long of a leave he needed and how quickly to build back up his hours when he went back.
So basically, she called to check up on me, and my employer had signed me in as "sick", though it wasn't ME who was sick, it was DS, and they apparently weren't supposed to write me in as sick. So the lady was telling me I should have done this and that, but I couldn't and it wasn't MY mistake, it was my employer.