Aw mama, yan talaga ang phase na yan, some babies suddenly lose interest sa bottle around 4-5 months, lalo na if they're starting to notice the world more, kaya parang distracted lang sila or mas gusto nila mag-play kaysa mag-formula haha. A few of my mum friends went through the same thing and it scared them too, pero usually okay lang, basta still kumakain overall at tumatae normal pa rin. Best thing is check-in with your pedia lang to make sure baby's weight gain is still on track and walang ibang signs na concern, better safe na, lalo na first baby mo kaya valid ang worry mo. For now, try feeding when baby's calm and not too distracted, maybe darker room or less noise? Kaya mo yan, mama!