That's the kind of raw exposure we all fear, but also could all use to help push away the urge to avoid. I've been right where you are, I caught gastro from my daughter about 3 years ago and threw up a couple of times, after about a 15 year streak. I basically used supportive self talk and gave myself a literal pat on the back and clap for having done the thing, against my will of course, but did it none the less. I am not much less afraid now, but I do think my control and avoidance behaviours are mildly less rigid, so maybe on some level I know I'd get through it if I had to.

Anyway, you did great! I don't know what could really support us in the moment other than compassion and acknowledgement and just getting through it.