IBS issues are keeping me from upleveling my business!

I have a successful private psychotherapy practice. You always encourage us to think about how to uplevel ourselves and step outside our comfort zone, and so I’m trying to do this by adding a 2nd group since my first one has had a waiting list for a long time. I figured this would create more value and serve more people while increasing my profit. Win-win, right? The problem is for some reason every Saturday before I start my two groups (they’re back to back), I start to feel extreme anxiety and need to run to the bathroom. I start to panic that I’ll feel sick while I’m in the group and need to run out of there, leaving my clients to wonder what is wrong with me. I can rationalize all I want that there’s no reason for the anxiety, that my groups are going great and if there’s really a problem, I can always just stop doing them, but the fear of feeling sick is causing me to feel sick and it’s a vicious cycle. I try to be present with the feeling of anxiety, to not resist, it, to use logic on myself, to tell myself that the worst that can happen is a feeling, but for some reason, in this situation, I can’t seem to find a way out. I don’t want to cancel my groups but I don’t know if I can continue in a state of digestive upset/panic the whole time either! Any thoughts? Thanks so much, Brooke!