Hi? ..am Pregnant And Can't Tell My Actual EDD,so I

hi? ..am pregnant and can't tell my actual EDD,so I did a ultra sound which gave me a due date of 24/08/2018, but I had no contraction or pain.so I did another ultra sound which gave me a due date of 04/09/2018. nothing has happened yet but ever since date 24/08/2018 I have diarrhea with stomach cramps every night and day.. my doc say my cervic is closed still .....am I supposed to worry abt the diarrhea and the dates