My 4 year old has lots of gas when going to the bathroom, watery stool, and this is happening for about 2 weeks now. she only goes once a day, twice a?

Mild malabsorption: Sounds like a touch of a bit of digestive problems. Whether it started as a little touch of a stomach flu, or she has a bit of intestinal irritation leading to some transient difficulty with digestion doesn't really matter. Change her diet to low lactose, low simple sugars, increase water and fiber and start a daily probiotic. If not better in a couple of weeks, pain, vomiting, then see doctor.

Dr Ferguson agreed

DIARRHEA: When diarrhea continues for longer time there is temporary lactose intolerance because of damage of the brush border of intestine causing deficiency of enzyme lactase. This causes acidic stools and gas. Avoid milk, ice cream. She can have yogort, banana, rice, applesauce, toast, chicken. Also avoid leafy vegetables. Give pedialyte, one bottle for each diarrhea.