Cross contamination at hot pot dinner is a major issue. In a proper modern hotpot restaurant you will be given two sets of utensils, one for raw and one for cooked.

Secondary issues are food not cooked properly.

Third: what are you having to drink with the hotpot? Beer and sour plum soup/tea (酸梅湯) are recommended. I always have one or the other at hot pot. (Especially if you are using the traditional charcoal fired pot with the chimney in the middle and the soup around that)

OR you are just not use to the spices or your digestive system does not handle the spices well.