How can one be so tired with no reason whats so ever..?

Yep. For no reason whats so ever I'm feeling quite dead and tired and like apatic... its killing me. I can't get anything done because I just feel like I m on sleeping pills? Why? What is this? This is damn scary.. I don't remember if I woke up earlier today. I think I did and I remember eating something but then it could be yesterday morning also? This is so confusing and I wanna scream. But I'm scared. But the otherhand I feel too tired to even care for it. What is wrong with me?