As it was said before - your Dad was attempting to protect you. I'm sure that if he knew how deeply it hurt you, he would not have done it.

Oddly enough, I have a very similar experience. My Grandfather died on a Sunday... my Grandmother died the follow day - Monday. My mother kept this from be because she didn't think I could handle two deaths in two days. Finally Wednesday rolled around and she told me. I was not only fucking pissed off at my mother for waiting so long, but I felt guilty for some odd reason.

Anyway, I am so sorry to hear about your loss. You have every right in the world to be mad at your Dad for not telling you - even if he thought he was protecting you. You are entitled to your anger, and perhaps it would do Dad some good to know exactly how you feel and how hurt you are.