I've had this problem for a while now but haven't done much about it, my doctor just says its my depression but I'm not sure. I have several anxiety disorders, diagnosed depression but probably Bi-Polar. But my problem is I'm mentally tired for a little bit not physically and then I go to being more aware and more physically hyper. But when I'm mentally tired I'm not depressed just feel light headed, kinda of like Its not negative or positive feeling more I want to sit and do nothing, but I'm not physically tired. Now when I feel this way I go play a sport for a hour or two and I find that helps but I don't understand why it feels like my mind is tired while my body can play 3 hours of basketball and or racquetball and not feel too tired. Almost everyday it goes for an hour or two of feeling mentally tired and usually light headed and not being able to socialize well to being extremely social and quick.

When I work with customers during a 8 hour shift during that time I'll go in and out of being able to speak well and be mentally "awake" to times when I'm completely zoned out and anti-social but I'm sad/angry just mentally tired, its weird and annoying.

Maybe I should go in for a blood test, it seems like this is physical not emotional. Right now I feel drowsy and unable to concentrate well but I'm happy but in an hour or two I'll be feeling mentally awake and wanting to go out and have some fun.:dizzy:

EDIT-the last two years I've lost 75 lbs and eat extremely healthy now, so I don't think its my diet.