I'm so sorry for your loss. My Dad as well has liver cancer currently. I havent thought yet about what life would be like without him, because I'm just so worried about his pain/suffering right now.
I know nothing I can say will help, but I just wanted you to know that you are not alone. You Dad sounds like he was such a wonderful man. I'm sure he knew just how much you loved him and cared about him. You honestly sound like you did everything in your power to be with him and care for him.
You are NOT a wimp at all. You are a person who loved your father very much and are having a hard time going on without him. Theres nothing wrong with that, and I think you just need to still live one day at a time right now.
All the best to you in what you are going through.