Sorry to hear about your loss Rollins. We feel a sense of helplessness when we lose a loved one, questions in our minds starting rising, like "Could I have done more? Why didn't I do this, or that...I regret not doing this, or that with the loved one, etc.
It's a normal process. As toad said, time heals. I recommend to people that have photos of their loved ones, to scan them and put these photos together in a short video or slide show with their favorite song. This has two purposes: It gives you a feeling that you are "doing something more" even with the loss, and it helps you heal faster. The feeling of loss will always be there, but not as much as it was initially, so you learn to cope with it. Having this slideshow or video, or even a scrapbook on hand helps you get over those "empty times" you'll encounter now and then.
Salute to your father, it sounds like we, America, have lost one of its finest.