It's really important to understand this cycle. Every time you decide to avoid a social situation, your anxiety lessens, which feels great in the short run. But in the long term, avoidance only leads to more anxiety because you don't get chances to practice skills and to discover that the reality is often less scary than your imagination.
The best way to reduce social anxiety is to practice socializing intentionally. You can set measurable and realistic goals, like "I will spend 3 minutes making small talk with the barista" or "I will compliment my coworkers twice weekly" or "I will stay at the party for an hour and talk to 2 different people, asking at least 3 questions each time."
Find a small way to start exposing yourself to social situations, even if it's just getting out of the house and going for a walk in the park among other people. The more you avoid, the worse it gets - even though it will feel great initially when you avoid.
I learnt to tell myself that it's ok to feel emotion during a stressful situation. 'it's ok to feel x when y'. When you tell yourself your not supposed to feel it, that's when it feels worse.