I'm sorry you're feeling unhappy.
I haven't lost a parent, but loss and separation are the hardest things we humans endure. There are so many layers to loss, most of them bad, unfortunately. I hear you describing the loss of him in your thoughts, and that is sad in its own way.
I do think the best way to honor someone is to remember their love and honor their wish for you to be happy, though I have trouble doing that myself sometimes.