Aww, mama, first thing, please check in with your OB right away, ha? Low-lying placenta at this stage needs proper monitoring, especially with baby's movements changing.
A few of us moms have been through similar worries, at ang best reassurance talaga is having your doctor keep a close eye on you through regular ultrasounds. The fact na wala pang bleeding is good, but movements changing ay kailangan i-discuss agad with your doctor para ma-track properly. Hang in there, you're doing great by being alert!