I'm really sorry for your loss.
4 years ago I lost my mother after 2 years of disease. The last 2 months has been a terrible suffering. I'll never forget watching her body and soul to empty completely day after day while I couldn't do anything about that.
So I think I can understand your feelings.
One time someone said me that by the passage of time I would have started leave behind the sad moments and started to remember the happy ones. Unfortunately that moment is yet to come for me. Each time I go to the graveyard I found myself in a loop living again those terrible last 24 hours.
My luck was that at the time I already started loving walking and so my long long walks was a way to fight back the bad moments of life.
I wish you the best and I hope you soon will feel again that happy feeling that the love of your father for you filled your heart, by remembering him.