@margitdill It's good to see you back here and letting us know where you are in your treatment. @val64 provided you with some helpful advice on staying home for awhile until you know how your body reacts to this new treatment. And yet, it's very possible you could be one of the people who don't experience diarrhea to that extent.
Still, being prepared is good advice. In your place I would wear an adult incontinence product (adult diaper) that is super-absorbent if I need to leave the house. I was prepared to do that when I had sudden bouts of diarrhea during radiation therapy.