That sounds like an absolute nightmare of a travel day—nothing like getting up at 2 AM only to find out your flight is canceled, and then having to navigate a whole new itinerary. The "heavy air traffic congestion" excuse sounds suspicious, but if there's storm damage in the region, that might explain some of the chaos.

At least you have some kind of alternative flight now, even if it means an all-day airport adventure. Are you able to find a comfortable spot to wait it out, or is it one of those crowded, miserable terminals?