What do you do when you are alone?

Maybe reword the sentence - how would you fight boredom when you are alone?

Recently I have found myself lost.  I cannot describe the feeling.  When I get home, I feel that the world is so bland and no feeling.  I feel that there is no colour to life.  I keep question myself why I keep feeling that but I cannot find the answer.

I used to enjoy every moment when I am alone by watching DVD, surfing the net, etc.

But what has changed? Why have I lost interest to everything?

Please find me an answer to this.