Hi, I understand your concern. The digestive system is strained in pregnancy due to hormonal effect-resulting in slow bowel movements , decreased digestion. The loose motion you had might come from, over eating, eating contaminated food,unusual or very spicy food. - take rest/ plenty of boiled water with salt & sugar, take very light food in small servings( boiled rice, butter milk, lemon water, coconut water, light tea or coffee - Observe for symptoms,In case of- - repeated loose motions with excessive cramping ,blood & mucus.in stools,signs of dehydration. - you have uterine contractions with increased vaginal discharge. You need to visit your doctor/ ER Thanks..