Ahhh, yang ni most likely Braxton Hicks lah, tu contraction practice je yang mana perut keras tapi pastu okay dalam 30 minit tu. Tapi since you're at 36 weeks and ada sakit ari-ari jugak, better check with your doc just to be sure, especially kalau intensity dia increasing or ada spotting sebab doc boleh confirm if it's just BH or kalau ada signs labour yang early. A few of my mum friends pun ada yang masuk office terus-terusan sampai labour day, so don't worry lah, tapi monitor ja closely and inform your workplace so they know what to expect!