My dad is dying soon

Title says it all. I'm only in my late 20s and I've been his primary care taker for most of my adult life. There isn't any other person I've spent more time with in my entire life. I'm trying to prepare myself for when the moment he's gone and I know it's going crush me all the same.

This will be my greatest loss in life so far. I know everyone goes through something like this. What did you do when a moment like this came? What did you do when it felt like you couldn't get up? I have know idea how I'm going to get through this, I just have to believe I will.

EDIT: Thank you for all your kind words and we'll wishes. My dad passed away September 23, 3:30 PM local time with his boys by his side. I'll love him and miss him every single day.