I'd say that 'functioning' means different things to different people.
If you'd define yourself as not functioning, then you're not functioning.
In societal terms, I guess functioning would be being able to make a living, to do all the normal day to day stuff, to deal with the things that life generally throws at you without going into uber-meltdown. That'd be my definition, or at least my idea of what society expects. (Though I have half a feeling that society actually expects a lot more.)
If you'd define yourself as not functioning, then you're not functioning.
In societal terms, I guess functioning would be being able to make a living, to do all the normal day to day stuff, to deal with the things that life generally throws at you without going into uber-meltdown. That'd be my definition, or at least my idea of what society expects. (Though I have half a feeling that society actually expects a lot more.)