Aiyoh, 31 weeks is still quite early la, so most likely Braxton-Hicks (kontraksi palsu), tapi memang scary kan especially first time! Senang je nak check: kalau sakit dia regular sama timing, pastu boleh time dengan jam, usually Braxton-Hicks; tapi kalau irregular dan makin teruk, atau ada discharge/spotting, kena jumpa doctor right away ya. A few of my mum friends said they panicked jugak at this stage, tapi alhamdulillah semua okay, just to be safe, call your clinic or OB-GYN la, they won't scold you for checking, and boleh set your mind at ease! Take care of yourself, get lots of rest