Ay normal lang yan, mama! Those vibrations are usually just baby movements, sometimes it feels like bubbles, sometimes like fluttering, minsan parang vibrating talaga especially when baby's hiccupping or moving fast kaya parang waves ng sensation lol. A few of us moms sa barkada namin felt the same thing around that time and it was just our babies doing their thing, pero since you're already 35 weeks, mas better na i-mention mo pa rin sa OB mo during your next checkup just to be safe and para ma-confirm na lahat's good, okay?