Wa'alaikum assalam! Itu Braxton Hicks contractions, sayang, totally normal even this early, especially kalau first pregnancy memang surprising! A few of my mum friends experienced it around second trimester onwards, tapi ada juga yang rasa early macam you. Since doc dah check dan cakap normal, that's the green light, tapi kalau jadi frequent or ada spotting/cramping yang pedih, just message doc lah untuk peace of mind, pregnancy anxiety tu real, so better safe than sorry kan!