Another bout of depression

I shouldn't say I am very depress today, I can still at least drag myself up and feel like keeping a journal today.  But this is one of those days I feel that life has no meaning, and there is absolutely no point to live on.  The feeling of quitting life is strong today.  Work overwhelm me.  I dragged working, I lost my energy to do anything.  I build up my business with a goal that I won't need to work that hard anymore once it is off the ground, keeping my family happy and wealthy.  But my business take a turn to a different direction and now I am constantly working extremely hard for money.  Training employees is hard, hiring gracous employees seem impossible, satisfying payroll is hard, deliver top quality services is hard, pleasing demanding customers is hard.  With a mind popping new ideas I want to do drives me crazy.  The inability of focus drives me nuts.  The thought of being not able to achieve success drives me insane.
I don't have much pain finally for the last month, usually pain are the source of depression.  But now the physically pain is gone, the pain of life seems to be just as bad.