My child and I both have the flu, so I am worried about my other 2 children?

2 things. A whole bunch of hand washing and nose wiping. Still , without med. Isolation those viral particles are now apart of your home . Decrease your concern by consulting your pediatrician. I'm thinking tomorrow.
Already done. It is very difficult to prevent the spread of illness within the family. You were contagious 1-2 days before you knew you wereill.