If i had the stomach flu and gave it to my daughter, can she give it back to me or would i be immune since i already had it?

Immune: If you had the same virus and you have recovered and you have a normal immune system, you should be immune and not susceptible from transmission of that virus back to you. (by the way, the best name for this is gastroenteritis. It's not really the flu because it is highly unlikely that the virus causing these symptoms is an influenza strain.).