Congratulations, You're Dead
While you're character in-game is actually 100% dead, that doesn't mean you're out of the game. This is actually very much expected for Curse of Strahd, and will likely happen a few more times. Right now, the game is going to carry on while you're dead, but I'll get you back in a soon as possible.
In the mean time, read over this page, but don't tell the other players what you've seen here (they'll see it soon enough, themselves).
Full character death is never any fun in a D&D campaign, so to soften the blow, I want to give you a few options. Read all these over, and take some time to consider what you'd like to do. Preferably, don't decide until the end of this session, and let me know what you'd like before the start of the next one so I can work it in narratively.
After reading these over, skip to 4. Hope the Party Revives You. This is the default for the short term (at least the rest of this session). While you think about what you'd like to do in the long-term, read that section so that you can continue playing for this session.
This is really kinda the default for DnD. Your old character has completely died, and will never come back. Your new character is a completely different person with different traits, difference experiences, and a different background. We'll come up with a reason why this person runs into the party, and they'll join up and follow around the rest of the crew.
As you can probably already tell, Barovia is a strange place with a few rules that are different from other DnD settings. Without going into too much detail, there is an in-universe feature that allows this to happen. Mechanically, this is what will happen.
There are a handful of NPCs in this campaign that would work well as PCs. Depending on where we are in the campaign, you may be able to pick one up. Let me know if you're interested in doing this, and I'll tell you if there's an NPC that you could play
If you choose this option, you would just take over that NPCs character sheet. This may require some serious dedication to roleplaying the character as their backstory and motivations may be important drivers for the narrative.
This is the default option for this campaign and what I will assume you're doing until you say otherwise. Even though this is the short-term default, this is still a totally fine way to approach your character's death in the long term. You'll be a ghost for a while, but the party may be able to figure out how to save you. If all else fails, you can fall back to one of the other options.
You're now a ghost (not the ghost monster type, but you're spirit has just been separated from your body). Here's what that means:
You've gained the ability to possess other characters (Can be NPCs or PCs). When you'd like to try to possess someone, just say to me: "I'm going to roll charisma against <character>" and nothing else.