Perut mengeras tapi baby masih aktif

Ooh kak, this sounds like it could be Braxton Hicks since baby's still moving well and the tightness came and went, but honestly dengan sakit pinggang tu I'd still get it checked with your doctor or midwife just to be safe, especially if this is your first time feeling it. A few of us had the same thing around this stage and the doctor said it was normal, tapi better safe than sorry kan, just to make sure everything's okayyyy and the baby's position is good.