If it continues and you have cramping and contractions go into emergency because chronic diarrhea is also a sign of premature labour.
My doctor told me that the main reason a pregnant woman gets diarrhea is its the body's way of removing bad toxins from the body fast! Any kind of substance that isn't good for the body that are put in fast food-fast food is considered any food that you don't cook yourself according to my doctor- will be expelled immediately from the body and because it has no real substance (like fiber) its exits as diarrhea! Definitely eat high fiber and watch the outside food!
As long as you're keeping hydrated, you should be ok for now. The main concern with diarrhea is dehydration. Keep a watch on it, and if you still have it in a day or two I'd call your doctor and mention it to them. In the meantime, you can also make sure you're eating a fiber rich diet and follow the BRAT diet - bananas, rice, apple sauce and toast.