I think it's a very good thing to miss a parent that much, knowing that many people don't. I think your Father has already forgiven you and appreciates all the love you feel for him. Carry on his image and his honor. I think these thoughts when I think of how much I miss my Dad and all the ways I'd want to have changed things before.
Forgiving ourselves is so hard, until then, how do we know love, though. Because we can only love others as we can love ourselves. Here's hoping you will find blessings in life's great challenges.