Again very tired today

Well Yesterday actually. Absolutely knackered and I slept for 10 hours. I wonder if I am ailing for something? Hope not I could do without anything else going wrong in 2006 and for a good start to 2007. I have a horrible feeling that there is something else wrong with me - perhaps just being a bit pessimistic there but whilst I still feel well something is nagging at the back of my mind about this tiredness.