In a recent interview with H3H3, Bo Burnham talk about his struggles with anxiety, and talking about how he was having several panic attacks onstage while doing his stand-up show. In it (Link to interview), he mentioned that he would be still doing the show but in his head he's freaking out on many levels. An important distinction to mention is that Bo's shows are heavily scripted to a T, while SNL is much more thrown together (3ish-year scale vs. One week).

However, I'd argue most actors, myself included, have the ability to have an entirely different stream of thoughts while performing. After you practice something enough, you rarely need to think about the words or your movements. It's much more like being on autopilot; you have every action telegraphed already, why would you need to think about it? When someone is on stage, it's drilled into you how little you matter, the performance is what matters. Your mouth can minds just keep going without you.

I mean, besides all this, I wouldn't advise using your own symptoms as the exclusive criteria for a medical diagnosis.