Do you have reason to believe you both ate the same thing? I'd be more inclined to think you have Norovirus just based on the fact that you're both sick. I mean, unless you both ate some really sketchy food at the same time.
Upper GI symptoms are typically actual food "poisoning" and would tend to happen rather quickly after eating. Like drinking too much liquor, your stomach picks up on the potential for trouble and reverses course, usually within a few hours of eating, but it could be as fast as 30 minutes.
Lower GI symptoms are foodborne infections - the bacteria take longer grow and infect your cells and/or brew toxins that are released into your gut. This would more likely be a ~12+ hour difference between eating and illness. Might even be days in some cases (or months if it's Hepatitis). Rarely it's the last thing you at that made you sick.
But going to back to my guess, Norovirus is the best of both worlds - coming out both ends and in a way that can only be described as "violent". The virus is also airborne so if you're sharing space with someone that is suffering, just being in the same room (or domicile) can put you at risk. Out of respect, I won't share the study that was done at a cheerleader competition that involved a vomit plume.
So...uh...yeah. Potentially jockeying for the bathroom sounds less than ideal.
. May have to go the wood route.
