Hi, thanks for using healthcare magic
It is possible that you were infected after using the tuna or another food you consumed yesterday.
In an adult ,
gastroenteritis, normally lasts only a few days.
During this time , you may want to consider(1) avoiding solid food and using mainly cool liquids,(2)
take the liquids slowly only 1 ounce or less at a time- if the stomach is not ready to absorb then taking too much will cause further
vomiting. You would use a small amount every 5 to 10 minutes
(3)probiotics either on their own or in yogurt may be helpful,
(4)rest and avoid excess movements which may provoke vomiting,
(5) there are anti emetic (vomiting)medication that you can also try
They should be available over the counter at your local pharmacy.
I hope this helps