Aww mama, yan yung gas bubbles or normal digestive movements na mas nagiging noticeable ngayon kasi ng hormones at growing baby, super common sa 13 weeks, a few of my preggy friends had the same thing! Pero if it's accompanied ng severe pain, spotting, or you're just really worried, better check with your OB lang to be sure everything's okay, kasi mas peace of mind para sa iyo.