How do you say good bye when you did not know your dad was dead?

I just found out yesterday that my dad died. His name was Kenneth Edward Towns 7/18/1949-9/5/10. We had been estranged for the last couple of years. But there was not a day that went by that my heart did not ache for him. I should have swallowed my pride and went over and made amends when I had the chance and now I never will. I loved him so much it feels like there is a whole in my heart. I just got out of surgery and when I was waking from anesthesia I was crying. i did not even realize it but I was crying. My doctor sat at the head of my recovery bed and told me I would be OK. But I don't really know that it is true. How will I be able to forgive myself for not making an effort when my dad was so sick and dying for two year. Granted I did not know he was sick, but I can only live in the what if's right now. I know I am a strong women but I have never felt more alone in my life, even though I have all of my family by my side I still feel so alone. I really hope the saying is true that our loved ones are looking down upon us and watching us and loving us, because I would have wanted nothing more then to tell my daddy, I was sorry and that I loved him and missed him so much. I hope he knows how much me and my siblings loved him and feel the loss of him so deeply, more deeply then any of us thought we would. You never know how much you love someone until they have been taken away from you and you don't get that closure you need. To my family and followers grab on to those around you and never let them go, don't forget to tell them you love them no matter what is going on in your lives. I will never get that chance and that is something I will carry with me always. Daddy I miss you so much it hurts more than the surgery I just went through. Love you always and I will try my best to focus on what the positives were and not the negatives. I am thankful you had your wife to be there for your in the end, I will always be sorry that I was not there. I love you always.