Haha sis, welcome to the hungry hungry hippo phase ng 2nd trimester! Totally normal yan, your body's working overtime kaya ang dami ng gutom, just make sure you're eating healthy snacks and staying hydrated like you're doing na. As for those movements and "kulo" feelings, 15 weeks pa lang so it's still early para sa clear baby kicks, pero possible na mararamdaman mo na ang subtle movements lalo na kung ito ang second baby mo or kung active ang baby mo, mas mahirap lang i-distinguish ngayon kung baby movement, gas, or bituka talaga haha! A few of us moms were surprised na naramdaman namin ng movements earlier than expected, pero honestly the best way to know for sure is to mention it sa OB mo next check-up so she can confirm if what you're feeling is baby or just your digestive system being dramatic. Keep noting when you feel them, at soon enough magiging super obvious na yan!