Hindi ka lang, marami sa amin ang nakaramdam ng ganyan sa early pregnancy, parang may pulling or tugging sensation, kaya naman common concern yan! Since normal ang ultrasound at labs mo, it's likely just your ligaments stretching as your uterus grows, pero I'd still mention it sa OB mo next visit para peace of mind lang, lalo na kung nag-worsen or may bleeding pa, better safe than sorry talaga.