I want to start by saying that social anxiety is a very common problem to have. Both your feelings and your response last year are entirely reasonable and valid. Social Anxiety affects about 1 in 18 people and anxiety affects about 1 in 5 people.
It is really great that you are interested in addressing your issue and that you have already taken a first step by asking here.
How can I get over my anxiety for another one of these lunches and hopefully not be so awkward, especially after my experience last year?
First of all - there isn't a "one trick solution" for overcoming social anxiety. There isn't a single thing I can say that could make it "go away".
Second thing - this is something you can work on and improve substantially. I have seen people transform their responses to anxiety and show substantial improvement over time using techniques of desensitisation.
Stuff you can do alone
There are exercises you can do for working on your social anxiety. I am using the Oxford sheets but there are some others. Here is a link to the [Oxford worksheet]
(http://www.oxfordclinicalpsych.com/view/10.1093/med:psych/9780195336696.001.0001/med-9780195336696-appendix-2) you can also get the book.
There is also the DARE response which basically tells you to:
- Answer "What if" questions like "What if I'm there and there is no one I can talk to" with "So what?"s.
- Accept your anxiety for what it is.
- Run towards the anxiety and say "I am excited by feeling social anxiety"
- Carry on and engage with the dinner.
Interpersonal skills you can apply
Gather your resources
One thing that helps is planning ahead of time what you're going to do. Preferably if there is someone at your workplace you trust you can tell them that you would like their help:
Hey, I have a hard time finding myself in large social gatherings and do better in smaller events. I really like the company and want to figure out how to participate in the Christmas party. Can I count on you for discourse during the party?
Think about interesting things that have happened to you in the last few weeks and you feel comfortable talking about.
Have a plan for if anxiety happens
This is a neat trick from dialectical therapy. If you become very anxious which is perfectly normal and happens to some people - it is good to plan for it. A self-soothing plan that includes something that doesn't distract you too much can really help.
For example - you can write down on a piece of paper something like:
If I get anxious, I will go to the restroom, pull out my phone and headphones and listen to the jazz song X. Then, I will take 10 long breaths.