Aw, congrats sa second baby! Normal lang yan, lalo na pag second pregnancy, sometimes mas hindi pa ramdam ng malinaw kasi alam mo na ang feeling, at ang baby pa naman ay napakaliit pa sa 12 weeks kaya parang bloating lang talaga ang sensation minsan. The good news is na may heartbeat na nakita ng doctor mo, which is very reassuring! A few of us moms din had this experience, one friend said mas medyo nahuli niya naramdaman ang movements sa second babe compared sa first, pero lahat ay normal naman. Maybe do a check-in with your OB kung gusto mo of peace of mind, pero based sa good ultrasound check mo, you're on the right track!