I wish there was something I could say that would help. Just know that I read your words and am so sorry you're struggling so with this. When my dad passed away in December of 2013 I hadn't been back to my hometown to visit him in close to a year. So I dealt with some guilt over that, and at never talking to him on the phone. The one piece of solace I have is that when I was there visiting that last time while he was still alive, I drove him from his house down to my sisters and we got to talk for about an hour. I'm glad I had that to hold onto when I was struggling with the guilt. My t helped me a lot with that.