A Couple Days Ago My Sister Came Home Sick She

A couple days ago my sister came home sick she threw up and I cleaned it but a couple minutes later I felt really sick I walked a
Outside and it didn't help this has been going on for 4 days now I thought I was pregnant I took a test its negative. I can eat but my nausea stop for like an hour then comes back again my mom is now sick feeling nausea I don't know what's going on