Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns.
As per your complain vomiting and severe 
abdominal pain can be due to 
Gastroenteritis or 
stomach infection..
It can also be due to food 
poisoning..
As it happened since friday and seems to be an acute illness so most common cause is infection and not any chronic illness..
I would suggest you to consult a Gastroeterologist and get evaluated and he can advise her antibiotics, anti-inflammatory painkillers, anti spasmodics along with anti emetics or anti vomiting medication like Ondensarton..
She should also take ample of fluids and oral rehydration solution to prevent 
dehydration caused due to vomiting..
Drink slowly as fast drinking can cause vomiting..
Take semisolid and light diet ..
Add yoghurt in diet , you can also take banana, curd and rice etc..
Avoid heavy meals and take sufficient rest..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.