Am I having contractions?

Just wondering how moms who've already delivered would describe early contractions? I woke up this morning with my entire stomach hard. It doesn't necessarily hurt... I'm just having mild cramping period-like pains and a lot of diarrhea. Could this be the real thing or just Braxton hicks? Everyone said I'll know with the real thing so I'm second guessing myself haha. I'm 38 weeks 6 days and haven't passed my mucous plug. I was 2 cm and 70% at my last appt 4 days ago. I haven't started timing yet but that will be my next step.