being a functional depressed person sucks.

I've been both functional and non functional with depression. I was non functional when physical symptoms manifested from depression and anxiety. I had a form of dizziness that lasted about two years and put me on my back and that came purely from anxiety/depression. Then there was a period of a year or so where my life was in the gutter thanks to addiction and I was pretty non functional then too. You don't need to be laid up in bed with razor blades to have very real depression. Hell, if people can walk miles with a freshly amputated limb then you can certainly leave the house when depressed.

And when you fail to do something "simple" due to depression, you get "you can't be depressed. You function"
Or something like that. It is frustrating, agreed.

Have you sought therapy? Taken meds? Joined a support group? Can you get help through work like an emplyee assistance program? If you are functioning then likely no one knows.

I can relate

I think my favorite thing about it is when my dad tries to cheer me up by telling me that when he was my age, he had already faced the possibility of going to Vietnam, etc., etc., so because he had it so bad, I should just be happy.