Sorry for your loss. No matter how long you know it's going to happen it still hurts. The hurt gets less after a while but it always seems to show up at unexpected times. The funny thing is when it does show up it will be a sight, smell or some activity that reminds me of Dad. The hurt is there but it makes me smile because of the memories he has given me. Sort of bitter sweet.
Those of us who can say dad was our best friend are rich indeed. I know many that, unfortunately, never had that kind of relationship. More's the pity.
Mine's been gone 3 years now and though I can't bring him back I can go to where he is. Miss him every day.
May God's love and the memories of your father give you some small amount of comfort at this time.