I appreciate the struggle that you present in this question. It sounds like you’ve been stressed with this for quite a while. Yet there does seem to be some other characteristics that would be important to identify.
First place to look would be in those social situations where this doesn’t happen. My guess is there are a few of them. Let’s see where you are with other people when it works and what makes that comfortable. Typically when there is this kind of anxiety, or panic, there’s a flipside to it. When there is something so acute that is causing this kind of arousal, there are other situations that don’t. You want to learn what they are and find out the difference.
I would make list of all the situations you’ve been in over the past month when you felt this anxiety. On the other side of the paper make a list of those times when you were with another person and felt fine or neutral. In particular look for the times when you actually enjoyed the engagement. What were looking for here is the difference: What causes you to be okay in one area and not in another?
I think this kind of analysis could be very helpful to pinpoint those things you need to feel good about in social situations.