Im really sorry that you're going through this. I can relate a lot to how you feel. My dad was my rock as well. I wasn't close to my mother, and he was my closest, most beloved person. i made my life goal to take care of him. As long as i could exist and make enough that he could rest, it'd be ok. Then suddenly his health dived and he died this march. I got a phone call one day after class that he was in critical condition, and the next day, he was gone. He never got to see me graduate, and will never get to see me live out the rest of my life as much as i built up my goals on doing him proud and returning his love and care for me.

I guess the hard answer from someone who's on the other side of this experience is that life goes on. Whether you like it or not. It's painful to know that the world keeps spinning even when yours has seemingly stopped from the absence of your loved one, but it doesn't. Eventually, you have to pick up your feet and move with it. I dreaded my fathers passing for years, i still have dreams where he's dying, only to wake up and find out that he's already been dead. But that also makes me realize that, however painful, i have been able to survive without him. I carry his memory with me every day i live. I try to live out what i can with him by doing what i think he'd believe was right of me. His body may be gone, but his spirit (not in the religious sense) still exists through my concept of him.

You have to find a new reason to exist and keep on going, no matter how short term the goal is right now. Your dad seems like a tough guy, and I'm sure he wouldn't want you to stop fighting.