Re: OOC
Unfortunately, it's the worst of the three options. You lose a level for real, you will need to adjust your character sheet. To be precise, you would lose 5,000xp, putting your new total at 12,300. If you had some more, I could have been nice and dropped you down to 15,000 so you could stay the same level.
I'll drop a scroll of restoration into the next big treasure for you.
Keep the old character sheet handy, I'll throw in some more 1000xp encounters to level you back up.
Is everyone healing up and ready to go find the source of the undead?