Why do I always feel tired?

So I don't know what's going on, I'm a 23yr old male, I've never had any problems with my health and I am fairly in shape, not IDEAL body, but still healthy weight... so it's not like I'm sick and obese, but anyways... recently I've been really really tired constantly. I get ok amounts of sleep, things haven't been going too well recently but I don't think I'm really to a depression state (yet), can it be my diet? But then again I don't really eat anything too horrible, I guess for the most part its home-cooked food, maybe I eat out 2, 3 times a week at most. What else can make me feel tired? sleep patterns? depression? diet? what else? I'm a little surprised how tired I've been feeling and I can't pinpoint one thing that would cause it... help anyone?