Third world country problem or young adult syndrome?

I feel tired, partly because I'm PMSing but mostly because I feel unstimulated. By life, by people, by work. I've lost the passion, the motivation or whatever you call it. I feel like I'm going through life without even thinking - I'm just on auto pilot everyday. That makes me kinda sad. Have I turned into one of them? God forbids.

I feel alive when I think I'm being useful or when I think I'm contributing. I'm doing neither.