If it's giving you this much anxiety perhaps it is smart to announce you are not going. They might be able to cancel the food that was ordered for you.
You did not specify when the party is, but if it's for example 21 December, you would have to remain in this state of panic and fear for almost 2 weeks. And I doubt that's good for your mental health.
I think this will be a fine opportunity to "break the ice" and start getting better acquainted with your fellow workers. I suggest you consider going.
I know that this may be easier said than done, but I encourage you to make an effort and try to go and socialize and meet new people. No need to have a "smart" or "witty" topic of conversation, just be ...
Why not use this opportunity to make some more acquaintance and friends?
Don't outright reject the idea of attending the party - Go ahead, give it a try.
What's the worst that can happen - that you'll have no new acquaintance - same as now? However, look at the bright side - you may actually find out some like-minded colleagues which whom you can start ...
Ahead of time, ask somebody you know in the company to introduce you to a few people. Making these introductions is one of the jobs of supervisors. Then say, "what do you do?" Then listen. People love to talk about themselves, and they won't notice you're anxious. Seriously.
You don't have to stay long. You don't have to make excuses for not ...
The accepted answer by Richard gives a good range of strategies which are appropriate to a wide range of situations. You're unlikely to go wrong taking those options.
The one I'm going to suggest is much more specialised, and often it won't be the right fit, but it's worth being aware of since occasionally it can be very effective:
Get inside the process ...
Full disclosure - I have a mild form of autism, and this is my strategy for social events like this. Yours may be more intense or have different triggers than mine, so adjust your plan to suit your own needs.
Have A Plan To Leave
Office Parties can be a lot of fun, even if social gatherings can be very awkward. Getting to talk to your co-workers in a ...
I've been to a couple of company Christmas parties. Besides offering a classy meal free of charge, they were unexpectedly well-worth the effort.
In the first one, there was an unexpected awards ceremony. It would have been less wonderful if I hadn't even shown up.
In the second one, there was an unexpected Christmas gift exchange game. The company ...
I'm not autistic (I don't think), but I'm definitely pretty far over on the social-anxiety side of things. I learned over the years to deal with these parties in a few ways:
I always try to go with someone, rather than on my own. Meaning, I walk over with a coworker that I'm comfortable with, and hang around with them. Often, this person tends to be much ...
Friendly neighborhood autist here, so I know how nightmarish "We just go with the flow" can sound.
First change your approach slightly.
Where are we going?
change that to: "Do they have a venue picked out yet?"
How many people are going?
Change to: "Who usually goes?"
When will it start?
For this one, ask someone who you get along with: "How ...