You should suspend the Nutrisystem program
for now, stay hydrated and follow a bland
diet-dry toast, rice broth or plain
rice, bananas, applesauce also known as BRAT diet (acronym).
Avoid greasy &spicy foods, dairy, fresh fruit and raw vegetables as well as alcohol.
Taking a drink with electrolytes is very important.
Coconut water is a good option.
There are other possibilities of course, but the aforementioned
stick out more.