I don't think "tomorrow" would give me time to do anything apart from speak to my family!
If the world was going to end tomorrow, there is not much I could do in such a short time. I would possibly go and have my dogs destroyed so they didnt suffer.
I read a book called The Last Policeman a while back where the world was going to be hit by a meteor destroying a lot of things and plunging the survivors into an ice age. One of the characters in the story also wanted to have his dog destroyed so it wouldn't have to suffer through it. I think that's a very compassionate thought.
I'd probably take a lot of sleeping pills so I wouldn't have to live my last hours in absolute terror; It also means you'll be asleep (or already dead) when the end comes.
There is something I would have to do, but once that's out of the way, I imagine I'd huddle with my loved ones and turn on some calming music, pray and wait. The sleeping pills isn't a bad idea. If I didn't have a family, I'd probably do that.
I'd just get on with my life and try to ignore it as best I could. Often these kinds of scares are only scares which don't eventuate. If like was in lock-down I'd just stay close to my family.