Even though we know we will one day lose the ones we love, you aren't ready when the time comes. And from cancer, I went through that with my Mom. Cancer didn't get her, but a blood clot she got from the treatments did. I hate cancer.
Heads up, brother. And take comfort in knowing a whole lot of other folks know exactly what you are feeling right now. What got me through was knowing all those times I saw Mom struggling, hurting and worrying about how long she had to feel so horrible was realizing she is free of that. Man upstairs has his arms around her now, and she is OK now.
So is your Dad. So, put that which is over away. Think back on the good times with him. Little things that did not mean much at the time, but are golden now. You did all you could for him. The Big Man has him now. And though you miss him, you are going to be with him soon enough.
This fall, when the Vols are kicking tail, you will wish he could be there with you. Guess what? He has the best seat in the house. Go Vols.