I had terrible diarrhea with my first and it turned out to be my prenatal vitamin. It was high in vitamin b and I already had enough vitamin b in my diet sobit had to go somewhere, lol. I had diarrhea a little bit with this one but usually accompanied by morning sickness. I've heard its pretty common in early pregnancy. It's not usually a symptom of miscarriage and there could be a simple reason behind it so I wouldn't worry too much. Good luck and congratulations!
Thanks for reassurance.