Thanks for posting your query.
Toothache can cause stomach virus as it is caused due to bacterial micro-organisms accumulated within the decayed tooth.
I would advice you to get clinical evaluation done by your dentist
Decayed tooth has to be restored or root canal
Take complete course of antibiotics-analgesics.
Maintain oral hygiene
Gargle using warm saline and chlorhexidine
Complete mouth cleaning has to be done.
Get routine dental check-up in every 6 months .