Aww mama, ang feeling na yan na parang may bubulong sa loob is actually pretty common sa second trimester, it's usually just the baby moving around, ligament stretching, or sometimes gas, hindi necessarily something falling out! But kasi 5 months pa lang and you're feeling something unusual like that, plus you're worried, mas better talaga to mention it sa OB mo sa next check-up para ma-ease your mind, better safe than sorry, diba, at alam mo naman doctors natin need to rule out things like incompetent cervix or other stuff na kailangan nila check. Ang baby mo is still secure sa uterus even if cephalic na siya, so don't worry too much, pero just get it checked out para matulog ka ng mahimbing!