Needed: Tips on Surviving Sadness

There was this article in a national newspaper about how to survive the life. It says,

Believe that nothing lasts forever. When you're happy, believe that you'll experience sadness soon enough. When sadness is in the present tense, trust life that happiness will come afterwards.

Oh yeah, I do believe that. There's happiness after sadness, sadness and then happiness. By experience I have learned. Celebrating happiness is something I am getting good at. No newspaper article or textbooks is necessary.

Before I go crazy, I think I need to learn to deal with sadness. You know, the kind that is caused by the one who you least think would hurt you but he did anyway? Unfortunately, the article doesn't say anything about surviving it.

Can you teach me?