This is so disappointing for you after making up your mind, but it's only 12 days (seems like a lifetime!). Mark it off on a calendar with a big cross.
In the meanwhile, detach, detach, detach. Just because he wants to put you down for his own reasons doesn't mean you have to buy into it. You have the option to just leave the room.
You know this will be over soon and you can post every day if you like. You'll get plenty of support here.