Link between diarrhea & contractions?

Amanda • Endometriosis fighter. Mommy of a 5yr old daughter and baby #2 due mid August!
Is it true there's a link between the two? Yesterday I had two painful contractions. And three bouts of diarrhea which makes no sense because I hadn't ate anything that would cause it! Yesterday and today when I stand up my whole stomach automatically tightens up too. Ideas? 😕