Sounds like braxtion Hicks. Real labor the contractions sent on or off. But when in doubt call your On / or midwife they will know what is best
Try drinking a bunch of water. Even a little dehydration can cause contractions or even premature labor.
Here's some advice on the signs you're in labor from MedHelp.org. You can also find it in the Week by Week section of the I'm Expecting app -- check Week 37. https://
www.medhelp.org/pregnancy-health/articles/7-Signs-Your-Baby-Is-On-the-Way/398
You can also find the symptoms of diarrhea and contractions in the app by going to the Pregnancy Diary from the home screen and selecting them from the Symptoms menu. Then click the menu bar in the upper left and select Symptoms Manual to see your symptoms.
http://www.medhelp.org/pregnancy-health/articles/Pregnancy-Symptom-Contractions/2106
http://www.medhelp.org/pregnancy-health/articles/Diarrhea-During-Pregnancy-Your-Symptoms-Manual/2112
If your contractions are on off then you aren't in active labor. It could be the beginning though.