I'm not a doctor, but from what I've heard and seen: many depressed people manage to put up a good facade.

(Of course, that doesn't mean that putting up a facade means that you are depressed.

Also going out and doing stuff is probably better for you than sitting at home, no matter if you are depressed or not. And if that drive to make you go grocery shopping or meet people is less than healthy, that's still better than losing all motivation for everything, I guess?)