Happy birthday baby girl

It's my little girl's seventh birthday today.  I wish I could celebrate her life.  I am so grateful for the time I have had with her and the the joy she has brought me.  But I am so sad for the pain this life holds for her and the heartache I cause her.  Life is just such a misery.  What is the point of any of us going on?
How could I be so cruel as to bring children into this Godforsaken existence?