PLEASE HELP!!! I have a question about the stomach flu. Can it be passed back and fourth over and…

PLEASE HELP!!! I have a question about the stomach flu. Can it be passed back and fourth over and over? Also have you ever had a 2 year old with it? What did you do? I need to prepare myself. My bf has it. He's nearing the end and today I started. So it's only a matter of time and she's NEVER been sick like this so I'm terrified.