Sayang, perut keras yang berulang tu boleh jadi Braxton Hicks (false contractions), yang memang normal kat trimester ketiga, tapi sebab kau ada rasa pressure bawah perut gak, better check with your doctor or midwife just to be sure, okay? Jangan tunggu lama-lama kalau rasa worse atau ada bleeding. One of my mum friends experience the same at 31 weeks, doc cek je, semua okay. Drink more water and rest, but get it checked soon, better safe than sorry!