Sakit macam mau period tu biasa je during pregnancy, especially kalau baby dah besar sikit, banyak mak I kenal pun ada rasa cramping yang sama at that stage, tapi better you check dengan doc to make sure it's just Braxton Hicks or normal stretching pains lah. 1.3kg at 28 weeks sounds good actually, baby growth is progressing well! Tapi kalau sakit tu severe or bleeding ada, jangan delay, go to your clinic or hospital terus okay, better safe than sorry kan.