There is no law that says you have to hang out with someone you don't get along with, when you are both attending the same event. Just go to the get-together, and if you happen to bump into that person there, just be civil and say hi, how are you. Then move off to go hang out with people there that you do get along with. I know for a fact that this works. Besides hearing how it has worked for others, it has also worked for me. I have a very good reason for not being able to stand my sister-in-law, due to something really nasty she did to me, but must occasionally be at the same family functions. I just say a civil hello, how are you type of thing, and move on to hang out with others there. Sometimes I will even go hang out with her dog!
I have no quarrel with the dog, and get along fine with her. Her two favorite activities seem to be sleeping and getting petted. Hey, I can do petting!
As for your anxiety issues, you need to find ways to occupy and distract yourself.
- Exercise. It generates mood boosting endorphins.
- Read funny stories and watch funny shows. Humor also generates endorphins.
- Eat healthy, and enough of it. A healthier diet will boost your immune system and is also good for your mind. Skimping on amount of food leads to depression, crankiness, and being more prone to get sick.
- Get enough rest. Being tired leads to depression, crankiness, and being more prone to get sick, too.
- Listen to and/or play music. This is mood boosting.
- Take courses, either in person, or online. Some of the online ones are free. The in person ones are a good way to meet people.
- Volunteer. There are people worse off than we are, who would really appreciate the help. It's also a good way to meet people, and boost your self image and mood.
- Take up a hobby or join a club. These are good ways to meet people who share your interests.
- Get involved in community activities. Attend town meetings, events at local libraries and other local organizations. Attend local sporting events, fairs, and art shows. Attend and/or participate in local theater groups. These are all great ways to meet people and boost your self image and mood.
- Employment/or self employment. Great way to meet people, boost self image, put money in your wallet, gain experience. Since you have been having trouble finding work as an employee, perhaps you should consider self employment. There are many types to choose from.
Give some of these coping methods a try. They do help some--I use some of them myself, so I know they work. 
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If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
Let him step to the music which he hears, however measured, or far away.--Henry David Thoreau