I am so sorry for your loss. It is normal for you to miss this wonderful & much loved patriarch of your family. Don't beat yourself up too much for having a life and being a responsible adult.
Of course it would have been nice to spend more precious moments together and that it didn't happen doesn't really make you selfish.
Please let yourself grieve, it is part of growing, learning in life to face this kind of loss. The trick is always to do it with a measure of grace.
I am so glad you found this site. It is full of really lovely people who truly do care....