His Father Suicided.
His best friend was killed infront of him.
He killed the girl that loved him.
His sensei was killed by his best friend.
One of his student is a rogue ninja.
His Mentor/Friend (jiraya) was killed.
And finally he discovers that his best friend wants to put the world into infinite genjutsu and he fights him.
You think your life is sad ?
Kakashi vs Tobi
Kakashi vs Hidan
Kakashi vs Kakuzu
Kakashi vs Akatsuki
Kakashi vs Obito
Rin Obito Kakashi
Kakashi Hatake AMV