Oof, that'd be a shock to the system, that might affect my pride a bit.
Italy or Greece, I suppose, not out of any overwhelming love for the culture as much as getting the chance be around so much tangible history.
Okay, Sure, I could move and chase civilization until it all collapses, OR I could try and start a new country from the ashes of my old one. If the current one collapses, that creates the necessary power vacuum I would need to have a go at creating my own and that is an opportunity I wouldn't want to miss out on. Plus I feel like I would lose the right to complain about anything with my country if I picked up and moved just because society collapsed and the going got hard. Instead, we could build a new country from the pieces of a former and build it better than before.
I would name it after my town in Animal Crossing, and then invent some storied BS history of how our name came to be.
If I HAD to move because the area is now unlivable for some reason, literally anywhere that would take me.