Sakit perut masa period memang biasa, tapi kalau ada pendarahan yang luar biasa banyak atau sakit yang tak tertahankan, better check with your doc jela to be safe, a few of my mum friends kena gastric ke or other things yang mimics period pain, so it's good to rule out. Normally kalau cramping biasa je and bleeding normal flow, it's just hormones doing their thing, but every body is different and doctors can give you proper advice based on your situation!