Aw, totally normal yan, mama! At 10 weeks, ang baby's heartbeat is super tiny pa and sometimes mahirap talaga ma-locate, lalo na kung first time mo or if the angle isn't quite right, a few of my mum friends had the same experience and nag-panic din sila. Best to ask your OB about it sa next visit kasi alam nila exactly kung saan hanapin based sa baby's position, or they might do an ultrasound instead to ease your mind and check on baby properly.