What Causes Constant Nausea Along With Frequent Bowel Movements?
The most likely cause is a mild viral gastroenteritis (stomach flu). These go around in communities and usually start with nausea and in some, vomiting, and later as it works it's way through, diarrhea. It sounds like you are having more frequent BMs but not necessarily watery diarrhea but that might be how it is for you.
Another possibility is that you ate something that your body is sensitive or allergic to, but this is lower on the list as you don't describe having had this problem before to any degree.
You should recover soon - in the next day or two. If not, then do go in to see your doctor. If you are in fact losing a lot of fluids and not able to keep up with drinking then go in to the urgent care where they can check your electrolytes and if needed, give you an IV and an antidiarrheal.
Apple sauce and fully cooked rice can help with frequent stools.
I hope this information helps.