Peter, so sorry to read of your loss. I can only echo what others have already said.
I lost my Dad eight years ago and it was totally numbing for quite some time. Try to think of all the really daft things he did, and all the stuff you laughed at, and the things he taught you, and the things you respected him for.
I know this sounds like a really bad cliche, but time, when enough of it has passed, will help you to feel better than you do now.