Honestly, I would go out and just enjoy myself without thinking about anything but myself...... For example, I would kiss and sleep with a stranger..I would go on a huge adventure with a kind eyed stranger.
I'd tell the woman I love about my feelings and move to a different state to spend the rest of the day with her if she feels the same.
If I am not the only one aware this is the end, probably people would panic and run like headless chickens in the street. I would sit some place with good view and watch idiots trample each other while eating junk food and laugh.
Go cry in a corner because I have so many things I need to do and can't do in just a day. Afterwards I'll call all my loved ones and tell them I love them.
Is reenacting the Purge an option? Because I'd like that. But if not? Probably confess to my crush, eat all the fudge I can find, and spend time at home with my family. And cry. A lot. Because those would be the last few hours I'd ever have with my family. On the plus side I wouldn't have to worry about paying for college.
Get to the top of the highest building in town.. which is a hotel and scream my heart out, then go into a room and get high :lol: or cuddle with someone.
Go find myself a nice big forest and never come out again. I like trees. I'd probably take my laptop and play minecraft.