The sad truth is that your life never will be the same - it may be worse, it may be better but it will never be the same.
I understand your anger and grief - I am a widow and I blamed myself every day for not doing... something. Now, looking back, how could I see what his Doctors didn't see? But at the time that anger at myself got me through some difficult days. First, you have to forgive yourself and let that anger at yourself go.
Blame is easy, including self blame. You obviously loved your father and he loved you - and you have to sort of focus on that during these difficult days.
It does get better. Really it does. There's no time table for grief. Everyone suffers for a different period, in a different way. You have to find a road that brings you comfort - sometimes it's religion, sometimes it's remembering, sometimes it's denial, sometimes it's anger. Eventually those stages pass and while you'll always miss him you will find peace.
I'm sorry for your loss and wish I had wise and wonderful words that would make you feel better - but I don't.
Just know that grief is not easy and blame does not help.