Personally, I don't think I would care much. I think I'm supposed to feel dread at the idea, maybe I would need to start planning how I would spend my last month alive, but I don't want to. I wouldn't do anything and I wouldn't care if I die.
Seriously though id probably do something that would keep my memory alive. Either unironically start a business or atleast taste what it feels like to do so or i'd finally get to developing the app that ive been delaying for a while.