Sleepless in Seattle

I have been having trouble sleeping through the night. For this entire week I have been waking up at 4:00a.m., and have not been able to fall back asleep. At work I have been so tired! I'm not sure what's going with me. Life is good right now so I don't know what my problem is. Maybe I should try counting sheep or drinking a glass of warm milk before my head hits the pillow. If anyone has any sleeping recommendations, I am open to suggestions.