Hey Stumpy.. Welcome..
What's your location? You in the Lower 48? I ask because, I was a Payroll Adminstrator for a major Corporation and, know a bit about this kind of stuff...
Here in the states, (Californina) we have State Disability, which sounds like you would qualify for. That will cover one year, if you are unable to work because of the depression, or whatever the Dx is.
Does your company have Long Term Disability? That normally will pick up after the SDI ends.
Check out if your doctor thinks you are unable to work and see what he will be willing to sign for.
If you are about to lose your job and, it is Because of the depression that you are unable to do it, you cannot be fired for an illness. And the depression is what made you incompetent, I'm guessing.. ?
Talk with your health providers and therapists and see what they say about your state of mind before you took time off. If it all points back to severe depression, you might be able to get the disability while you recover completely.
Good luck and keep us up to date.