Can the stomach flu mess up your period schedule? I ended up going to the hospital after throwing up every 30 minutes for 8 hours straight. I couldn't keep water down! It started at 5am on Friday, got home from the hospital at 11pm that night and I've been recovering + on meds yesterday and today. Period is due today but I've just had a few cramps here and there since Friday. I was wondering what the flu can do to your body though? When do you guys think I can expect my period? Thanks!